Bulldozers

While it is not certain who actually invented the very first bulldozer, many historians give credit to an American by the name of Benjamin Holt. They claim that he built the first bulldozer in 1904.  He originally called it a caterpillar or a crawler tractor.  

According to Deas Plant, an expert from Queensland, Australia, Benjamin Holt only developed a chain tread that was endless for his steam traction engine toward the end of 1904. However, in England, the Hornsby Company converted a steam traction engine which was wheeled to a crawler or tracklayer format.  This was based on a patent that was granted to their chief engineer at around the same time. Both of these developments were quite simply track laying traction engines.  Neither of these were a bulldozer.  But truth be told, the version by Hornsby was much closer to the bulldozers we have today.  This is because the Hornsby version was steered by controlling power to each track.  The machine built by Holt had a tiller wheel out in front of the tracks.  But interestingly, around 1913 to 1914, Benjamin Holt purchased the patents that were held by Hornsby. 

A photographer who was working for Benjamin Holt actually coined the name caterpillar. He was taking photos of one of Holt's crawler or track-laying tractors. While looking at the upside-down image of the machine through the lens of his camera, he commented that the top of the track looked like a caterpillar while it was undulating over its carrier rollers. Benjamin Holt adopted the name for his track-laying system as he liked the comparison his photographer had made. He used it for several years prior to the formation of the Caterpillar Tractor Company. In August, 1925, the Caterpillar Tractor Company was created.  This was done by merging the C. L. Best Gas Tractor Co and the Holt Company. 

But before the actual bulldozer that we know was invented, we should understand that the blade of the bulldozer was in use prior to the invention of any of the tractors.  The bulldozer blade consisted of a frame with a blade at the front.  Two mules were then harnessed into the frame of the blade. They would then push the bulldozer blade into a pile of dirt which was dumped by a cart.  They would either spread the dirt or they would push it over a bank to fill a gully or a hole. It became very interesting when you wanted the mules to back up in order to make the next push. 

It seems that the word bulldozer was coined from the actual bull.  It is in reference to the habit of bulls which are stronger pushing the weaker bulls backwards in contests of strength.  These contests are considered to be not-so-serious and most often occur when it is not mating season. During mating season, these contests become very serious.  Technically, the word bulldozer now refers only to a blade that is shovel-like. It has been over a period of several years that we have come to associate the word bulldozer to mean the vehicle in its entirety, consisting of both the blade and the crawler tractor combined.