Unit Rig

Unit Rig was founded in 1935 by Hugh S. Chancey and two partners, Jerry R. Underwood and William C. Guier, who formed a partnership to build a rotary drill rig for oil field work that was more mobile than existing designs. The group based the company in Tulsa, Oklahoma. By 1947, the partnership between the men was beginning to break down when Underwood died, leaving Chancey and Guier as the remaining partners. Guier eventually took control of Unit Rig and in 1951 sold it to Kenneth W. Davis, who already had several oil-field related businesses under the parent company name of Kendavis Industries International.

During the 1950s, Unit Rig began to diversify its products away from the limited oil-field products and looked towards mining products to utilize their manufacturing facilities. R. G. LeTourneau had already adapted compact electric drive wheels to construction machinery with great success, prompting Unit Rig to investigate the possibility of building a truck and finding a suitable client to take the finished machine.

By 1960, the M-64 prototype truck was completed using General Electric drive systems and featuring special Goodyear low-pressure tires for the suspension. This truck was not a success; however, Unit Rig went on to be a very successful maker of off-highway dump trucks sold under the brand name of Lectra Haul (due to their electric drive system).

in the 1970’s, a large order for M200 trucks was received, to be shipped to the USSR. At that time, the US government did not allow trade with the Soviet Union. The company negotiated a deal with the Canadian government, allowing shipment from Canada, providing the company could verify the use of 40% Canadian materials and labor. The trucks required large quantities of steel, the majority of which was purchased from Canadian companies, and shipped to the Tulsa plant for fabrication and machining. Final assembly was done in Canada. The M200 utilized a diesel engine to generate power for the GE electric wheel motors. The wheel motors were the most expensive component of the M200. In 1976 the wheel motors cost $ 64,000 apiece, which equates to approximately $500,000 each in todays dollars.

Lectra Haul was eventually sold to Terex then to Bucyrus Erie, who were taken over by Caterpillar Inc. around June 2011. Some Lectra Haul trucks are still sold alongside Caterpillar's own trucks but are branded as Unit Rig.

Unit Rig trucks enjoyed a reputation for a simplified customer friendly design with very little requirement of parts during operation. A large fleet of Unit Rig trucks were sold in countries falling in Arctic circle and they proved to be survivor. Their solid rock like performance forced competitors to spend huge resources on R&D to match the performance in not only in sub zero but in sub Saharan hot environment. Unit Rig had just 4 engineers to design whole new trucks and a small but very experienced support group. In early 90s, Unit Rig brought in the first truck that had design intent for a min 8000 hours operation per year and successfully proved it. 8000 hours of operation means an availability over 92%.

Unit Rig launched industry's first AC drive 150T (MT3300AC) truck with GE Invertex drive followed by 240T AC (MT4400AC) truck. Both trucks wrote new chapters in TCO - Total Cost of Ownership which is an indicator of life time expenses made by a client on parts, fuel and Capex.

Unit Rig' truck design philosophy probably prompted later day's Linux like open source programming.

In 1998, Unit Rig executed the mining industry's largest single order for supply of 160 trucks to Coal India Limited.

• Haul truck

• Orlemann, Eric (2012). Haulpak and Lectra Haul: The World's Greatest Off-Highway Earthmoving Trucks. Wisconsin: Icongrafix. ISBN 1583882928.