Method and apparatus for depositing prearranged retroreflecting elements onto a road surface

#As is well known, many experiments have been carried out in the more evolved countries to try to improve night-driving safety, even under foggy and rainy conditions, by using special road markings designed to provide an efficacious guide for the motorist. It has not been possible to achieve this goal, however, using conventional materials. The difficulty has been due to the fact that whenever the retroreflecting elements, located on the marking strip, become covered with a film of water they no longer function as originally intended.

#Mr. Ludwig Eigenmann has been awarded patents covering retroreflecting elements that are visible even under rainy conditions. These Patents include, for example, U.S. Pat. Nos. 4,072,403, 31,291, 4,411,553, 4,607,978; the Swiss Pat. No. 637,716; the European Pat. No. 83108302.7; and the Italian Pending Patents No. 22934 A/82 and 25023 A/82. With the conventional marking strips, inexpensive glass beads are haphazardly spread over the strip, but with Mr. Eigenmann's composite organic retroreflecting elements--which are necessarily more costly--these elements have to be so applied as to obtain the maximum retroreflecting efficiency.

#Up to now, the depositing of the Eigenmann retroreflecting elements has been best done from an inclined-plane arrangement, using vibration or other means. The obtained road-mark-efficiency has been good and very much better than that obtained with the conventional types of retroreflecting elements. The obtained efficiency is very good under rainy conditions, but is not the maximum obtainable, due to imperfect mechanical depositing and consequent imperfect element positioning. The high cost of the elements does not permit obtaining an efficiency that is less than the maximum possible.

#The enclosed schematic diagram shows a preferred arrangement of the device for carrying out the object procedure.

#The reeled conveyor sheet, upon which the retroreflecting elements "A" are positioned at preestablished distances, is indicated as "B". Sheet "B" passes over the sharp angle "C" and here is where the elements "A" are detached. The detached elements are indicated as "D" when deposited onto the road surface or existing road-marking strip, either one being indicated as "S".

#After passing over the return roller "F", sheet "B" winds onto the rewind reel "E". This rewind reel is actuated by known means not shown in the diagram and draws sheet "B". The assembly is moved, in the direction shown by the arrow, at a speed commensurate with the speed of sheet "B", so as to obtain the desired distancing of the elements "D". The said movement is obtained by known means not shown in the diagram.

#The prepositioning of the elements "A" on sheet "B" is done before reeling takes place, and is not disturbed during the unreeling phase, due to a certain degree of adherence provided by either the contact surface of the elements "A" or the contact surface of sheet "B". If the surface of sheet "B" has the adherence capability, the surfaces of the elements "A" will be treated with the detaching polymer. If the surfaces of the elements "A" have the adherence capability, the surface of sheet "B" will be treated with the detaching polymer.