The objectionable presence of litter scattered over relatively large areas, such as streets, highways, parking lots, parks and other recreational areas is both unsightly and expensive to remove. While prior art equipment for removing and collecting litter are generally more efficient than manual labor, to my knowledge, such equipment fails to remove all litter from the ground, especially over terrain of varying contour.
A common type of litter collecting device typically includes a single pick up roller or drum rotatably supported on a frame moveable over the ground. Resilient fingers project from the roller to entrap litter therebetween during rotary contact with the ground. The entrapped litter is then lifted from the ground by the fingers as the drum rotates. A smaller, elevated brush roller downstream from the pick up roller removes and transfers entrapped litter from the fingers for discharge into a trash bin carried by the frame. (See, for example, U.S. Pat. Nos. 3,923,101 and 3,993,141 to Donahue).
While the above device is somewhat effective to remove certain types and quantities of litter scattered over relatively large areas, the rotating pick-up fingers often fail to initially engage or retain entrapped litter for subsequent removal by the elevated brush roller. Consequently, substantial quantities of litter remain on the ground. Additionally, substantial quantities of litter lifted by the fingers are often ejected back onto the ground by the rotating brush roller.
Another type of litter collecting apparatus utilizes a tandem pair of identical, oppositely rotating rollers, as disclosed in U.S. Pat. No. 2,916,753 to Redpath et al. Each roller supports respectively intermeshing plural fingers engageable with the ground. This type of prior art apparatus tends to lift greater quantities of litter from the ground than the single roller-elevated brush arrangement discussed above does, since litter not grasped by the front roller fingers is usually lifted by the rear roller fingers.
To transfer litter to a downstream conveyor for discharge in a rear trash bin, Redpath et al uses plural elevated, fingered rollers meshing with front and rear fingered, ground level rollers. The elevated and ground level rollers convey litter downstream along an arcuate transfer path above the ground level rollers. Difficulties are encountered, however, in maintaining precise control over transfer of litter entrapped between the fingers of the ground level rollers. Specifically, there is a tendency for the elevated rollers to redeposit entrapped litter onto the ground since the fingers cannot maintain positive control over all types of litter for movement to the conveyor within the same transfer path. Also, whereas the rollers yield to uneven terrain, the equipment is complex and cumbersome, increasing production and maintenance costs.
It is accordingly an object of the present invention to provide a litter collecting apparatus capable of completely removing all types of surface litter.
Another object is to provide an apparatus having a unique pick up roller assembly capable of maintaining positive control to accurately transfer litter from the pick up rollers to a trash collection drum with no appreciable spillage.
Yet another object of the invention is to provide a mobile apparatus that automatically picks up bottles, cans, paper and other litter scattered over relatively large areas, such as streets, highway areas, parking lots, drive-in theaters and recreational areas.
Still a further object is to provide an apparatus having a pick up roller assembly that vertically yields to uneven terrain, preventing damage to working parts by knolls, depressions and the like.
Yet a further object is to provide an apparatus that is simple in construction, economical and can be towed by a lightweight automotive vehicle to completely remove litter within the travel path of the vehicle.
Still another object is to provide a litter collecting apparatus that is rugged and operates reliably in hostile environments.