Abstract: An improved brush cutter having an upper feed control member with stop, forward, neutral, and reverse positions also has a lower feed stop member with selectable sensitivity. Another aspect of the invention is to predict the feed roller shutoff point according to the rate of engine deceleration. According to another aspect, when the feed rollers stop feeding material into the cutters, to overcome drag on the cutters, a controller stops the feed rollers and then reverses them for a short time, and then reverses the rollers again if the problem is still present. To prevent jamming, a pressure switch senses when oil in a hydraulic motor system for rotating the feed rollers is too high and the controller momentarily reverses the feed rollers and then causes them to go forward, a cycle which can occur several times until the feed rollers are no longer stalled.

Abstract: A control system for a drilling machine is disclosed. The drilling machine includes a rod driver for driving a string of rods into the ground, and for removing the string of rods from the ground. The drilling machine also includes a magazine for storing rods near the rod driver. A rod transfer mechanism moves rods between the magazine and the rod driver. Vices are used to make and break joints between the rods of the drill string. The control system includes joysticks equipped with switches for controlling operational sequences of the vices and the rod transfer mechanism.

Abstract: A system, apparatus and method for automatically limiting the thrust force applied to a drill string during an underground boring process, in order to prevent the deformation or collapse to the drill rods due to reaching the yield point of the rods. One or more drill string characteristics that have an impact on the yield point of the drill string, or portions of the drill string, are determined. The yield point of the drill string or portion is computed, where the yield point is computed as a function of the drill string characteristics. The thrust force imparted to the drill string is adjusted in response to the computed yield point.

Abstract: A control system for a drilling machine is disclosed. The drilling machine includes a rod driver for driving a string of rods into the ground, and for removing the string of rods from the ground. The drilling machine also includes a magazine for storing rods near the rod driver. A rod transfer mechanism moves rods between the magazine and the rod driver. Vices are used to make and break joints between the rods of the drill string. The control system includes joysticks equipped with switches for controlling operational sequences of the vices and the rod transfer mechanism.

Abstract: A system, apparatus and method for automatically limiting the thrust force applied to a drill string during an underground boring process, in order to prevent the deformation or collapse to the drill rods due to reaching the yield point of the rods. One or more drill string characteristics that have an impact on the yield point of the drill string, or portions of the drill string, are determined. The yield point of the drill string or portion is computed, where the yield point is computed as a function of the drill string characteristics. The thrust force imparted to the drill string is adjusted in response to the computed yield point.

Abstract: In order to place dry granular materials into the subsurface of the soil without mechanical tillage, minute charges of the material are carried by high pressure jets of liquid, such as water, down into the ground from a series of side-by-side nozzles that simultaneously fire the jets toward the ground at regular intervals as the nozzles advance along a path of travel. Instead of passing through the water pump and the sensitive jet-producing nozzles, the granular materials remain separated from the water until the jets have issued from their nozzles and are passing through a ceramic mixing chamber in which a venturi is located. During the short pauses between successive blasts from the nozzles, material is continuously fed into a collecting chamber for each nozzle to form a small charge. As the water blast takes place, the charge is automatically drawn into the venturi and carried out of the machine by the high pressure jet.