The digger derrick is a specialized vehicle-mounted machine particularly developed to excavate or dig holes and to set into position electrical and telecommunication poles. This competent machine can also be called an earth borer because it has an attached auger for drilling cylindrical holes into the ground.

This unique piece of equipment can be used in several different ways when it is mounted on a commercial vehicle from which comes the term: digger derrick truck. Three major useful applications that this machine can perform are to drill the hole, then lift the pole and set the pole in place.

Drill - Basically, the primary purpose of a digger derrick is to drill a hole. Before starting to dig a hole, you should always check for any potential hazards you could encounter during the operation. Parking brakes should be well engaged and hydraulic outriggers should be deployed for stability. To properly operate this machinery, the digger should be positioned directly over the point where the hole is to be excavated. A moderate steady downward rotational force will produce the most efficient digging motion.

Lift - The loading capacity of the machine should be checked to see how much load can be attached to the boom in several different working positions. The best thing to do is to check the manufacturer’s manual to avoid overloading. After excavating a hole, the auger can be folded and the boom can be used to lift a post by installing a wind-up cable line to the tip of the boom.

Set – The digger derrick is equipped with a pole guide and boom flares specially designed to set poles. Pole guides are used to align and position electrical and telecommunication poles. Be cautious in setting up poles because severe injuries may happen if the pole guide is mistakenly used for pole lifting and pulling. You have to consider that a lifting sling is used for the lifting of the pole, not the pole guides.

The Rise of Digger Derricks

During the end of World War II, two individuals contributed to the advancement of utility trucks by developing a machine to dig holes for utility poles. In 1945, Terex Utilities created the first such vehicle and named it the Tel-Elect digger derrick.

The machine was driven by the truck’s power-take-off (PTO) and used a Ford differential to maneuver the auger. This revolutionary invention provided a state-of-the art solution to the usual way of digging telecommunication and electric utility poles almost entirely by hand. The old-fashioned way of boring a hole was replaced by the use of the digger derrick apparatus and was such a great accomplishment for the electric and telecommunications industries.

Today, this utility vehicle is manufactured by Terex, Altec and LiftAll for successful use in the field.

Safety Concerns

All operators of this equipment should comply with OSHA’s rules and safety guidelines. They should read and study the operator’s manual before using the equipment. The manual gives ample insight in preventing foreseeable accidents that could happen in the working area. It also suggests possible ways to deal with this kind of dilemma should it occur.

An important step to maintain safety with the digger derrick is to conduct an inspection before, during and after the operation to make sure that the equipment is in good working condition. The operator should also bear in mind that when transporting the vehicle, the boom should be in a lowered position prior to travel away from the work site.

The digger derrick apparatus and vehicle are one of those innovations that greatly changed the way a particular job was done, specifically the digging for and setting of poles for electric and telecommunications lines. What a positive solution to help the workforce of these industries!