Elevating scrapers are designed to be self loading, so long as ground conditions are favourable. This means that the scraper is not dependant on having a dozer to assist with push loading. Instead of an apron at the front as you would find on a conventional scraper, the elevating models have a hydraulically driven elevator consisting of two chains equipped with a series of crossbars or “paddles”, which assist in lifting the material into the bowl whilst also preventing build up of material at the front. Depositing of the material is different again to conventional scrapers, with the fitting of sliding floor in the bottom of the bowl. You can clearly see the sliding floor in this shot of a John Deere JD760-A model.
This 1970’s Caterpillar 633C, was at the time the company’s largest elevating scraper with a bowl capacity of 32 cubic yards. Indeed Caterpillar are the only manufacturer featured in this article that continues to produce scrapers of both elevating and conventional bowl designs.
Michigan’s first in house designed motor scrapers were launched in 1957. They offered three models, 110, 210 and 310. This Michigan 210 elevating scraper had a bowl capacity of 18 cubic yards. One thing I notice in these photos is the positioning of the lift rams. One would think with all the chrome exposed in close proximity to the ground, they must have suffered a fair amount of damage overtime.
Wabco (Westinghouse Air Brake Co) were keen promoters of the elevating scraper concept throughout the 1960’s & 70’s. One of their largest models was this 32 cubic yard, 333FT which was a twin engine variant. It was only superseded in size by the 353FT, which was introduced in 1977 and had a 36 cubic yard bowl capacity. Sadly heavy operating costs on the big elevating scrapers saw sales drop off dramatically, signalling the end of Wabco’s involvement in scraper manufacture. The model in the shot here is seen working in the UK in 1978.
Here is a cracking video from our friends at the Danish Construction Channel, of what looks like a well preserved Wabco 333FT elevating scraper complete with rear fitted ripper, working in a lime quarry in Denmark
Lookout for more machines from the Digger Blog archives soon.