The Thermo-Lay was designed in 1977 by Art Leafdale, who was a street superintendent for the City of Thermopolis, Wyoming at the time. Mr. Leafdale was not pleased with having to send six people and four pieces of equipment to patch the asphalt streets in Thermopolis. He knew in his mind that there must be a way to carry EVERYTHING needed for permanent asphalt repair on one piece of equipment which should cut the patching crew down to a two man crew.
Mr. Leafdale set out to build a machine that would carry 3 3/4 cubic yards of cut-back (cold mix) asphalt, 200 gallons cut-back tack oil, a hydraulic pavement breaker (jack hammer), and a vibratory plate compactor. He knew that the asphalt mix had to be heated for the best compaction and that the asphalt tack oil had to be heated to get to a spraying temperature. Art decided to build a tack oil tank beneath the asphalt mix hopper, so that when the asphalt tack oil is heated to a spraying temperature, it would in turn heat the asphalt mix. Other patching machines built at this time heated inefficient air. Mr. Leafdale also knew from past experience that shoveling the heated mix out of a dump truck apron was both wasteful and back breaking work for the patching crew. He decided that a screw conveyor (auger) feed system would be able to distribute the desired amount of asphalt mix and could dispense the heated mix down a pivoted chute and into the repair section.
Mr. Leafdale was by trade a machinist and had a large number of friends in a lot of different trades. He asked Ed Knight, a close friend, to help put Art's design and blue prints into steel form. The first prototype was a great success, as Art had envisioned it would be. He let the City of Thermopolis try his new machine while he prepared to apply for his patent. After a short period of time, he approached another small city in Wyoming and inquired as to their interest in such a machine. Upon selling the first prototype to the City of Lovell, Art looked for someone that might be able to manufacture his patent pending machine. He asked Wayne King, and old friend and pipeline contractor, if he would be willing to manufacture these machines. The rest is history. Art did the promotion and selling of his new product while Mr. King's pipeline company manufactured them. Several machines where sold during this period in 1978.
After his health started to deteriorate, Mr. Leafdale retired to Arizona. Prior to his death, he sold the manufacturing rights to his newly patented machine to Northwest Manufacturing & Distribution in Billings, Montana and to R.G.S. Industries in Joplin, Missouri. Northwest purchased the right to sell these machines in 16 western states, Alaska, Hawaii, and Canada. R.G.S. Industries purchased the right to sell in the remaining 34 states. Northwest Manufacturing set up a distributor network and relied heavily upon them for their sales. In 1986 R.G.S. Industries sued Mr. Leafdale's widow for the right to free distribution without paying royalties. This suit released both R.G.S. and Northwest Manufacturing from their distribution contracts.
About this time (1986) Tim King, Wayne's son) was granted a second patent on the design improvements over the original patent. In 1990, Northwest Manufacturing purchased the original patent from Mrs. Leafdale. Several improvements to the machine have evolved through the years. In 1985 the Thermo-Lay tack oil tank was replaced with heat transfer oil, allowing the asphalt mix to be heated up to 400 degrees F. A separate tack oil tank was also added that uses the same heat transfer oil a heating source. Hydraulic steel insulated doors, a hydraulic lift for the plate compactor, hydraulic arrow board, sanding attachment, integrated hose reel for the three fluids, and and automatic pilotless propane ignition system were all added during this time.
During the past 5 years, Tim and Wayne have designed several improvements to the Thermo-Lay. The evolution away from manual activated hydraulics has led to solenoid activated hydraulics. We have found them to be trouble and maintenance free, while allowing us to make several unique safety improvements by utilizing the electronic capabilities of these solenoid valves. For instance, the hydraulic flow rate can easily be regulated per function using an electronic throttle and the electronics from the solenoid valves. being able to have dual controls (rear and in-cab) has provided the flexibility that more customers are demanding. The hydraulic trash bins have been one of the best received improvements since the machine's conception, by providing large storage, a short turning radius, low loading height, and hydraulic dumping. The Inteli-Temp heating system has been in design and testing for several years and has also been given high praise for it's time and economic savings.
Northwest Manufacturing continues to change and re-design the Thermo-Lay to meet the growing demands of this machine. While adding features, we always have the D.O.T. GVW rate standard as the primary consideration. We continue to make the lightest machine on the market, the largest capacity, safest design, and still maintain the weight requirements in combination with the shortest turning radius possible.