Tool driving or impacting – With work engaging means supporting drive – Anchored to work
Reexamination Certificate
2000-02-11
2001-07-10
Smith, Scott A. (Department: 3721)
Tool driving or impacting
With work engaging means supporting drive
Anchored to work
C173S037000, C173S042000, C173S187000
Reexamination Certificate
active
06257350
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to horizontal directional drill machines. It relates particularly to a stakedown assembly for a horizontal directional drill machine.
BACKGROUND OF THE INVENTION
A horizontal directional drill machine is a common and well-known machine for installing pipes beneath the ground and generally parallel to the surface. These machines are used in many different applications and are available in a wide range of sizes. Typical applications where a horizontal directional drill machine might be used include the installation of fiber optic cables, electrical cables, gas lines, water systems, or sewer systems. Horizontal directional drill machines are commonly rated in terms of pull-back capacity. Some machines for smaller applications have as little as five thousand pounds of pull-back capacity. Other machines are available with a pull-back capacity of as much as one million pounds.
One alternative to a horizontal directional drill machine is the traditional trencher machine. A trencher machine simply digs a trench into the ground, and after (for example) pipe is laid down in the bottom of the trench, the trench is filled and the pipe is buried. The advantage of a horizontal directional drill machine over a trenching machine is that a pipe can be buried in the ground over long distances without digging a trench. Thus, a horizontal directional drill is particularly desirable when a trench would be difficult or too costly to dig. For example, a horizontal directional drill machine finds particularly advantageous application for installing pipes under roadways, where destruction of the road is expensive and inconvenient to travelers, or under a waterway like a river, where trenching would be impossible.
A unique aspect of a horizontal directional drill machine is the special drill head that is attached to the front end of a pipe to be laid. The drill head has an angled shape which allows the operator to change the direction of the pipe after it has entered the ground. Direction changes are achieved by stopping the pipe and drill head rotation and orienting the drill head at a desired angle. Then, by pushing on the drill pipe without rotating it, the drill head and attached pipe will veer in the desired direction. Thus, by effecting directional changes to pipe travel, a pipe might enter the ground at an angle, travel horizontally over a long distance, and exit the ground at another angle. This ability to change the direction of pipe travel also allows the operator to steer the pipe around underground obstacles like boulders.
In addition to pushing forces which must be applied to the pipe as it is inserted, it is often necessary to pull back on the pipe. This may be necessary when a direction change is not completely successful on the first attempt, or when an underground obstacle like a boulder is encountered. The machine then pulls the pipe and drill head back to permit a direction change.
The push and pull forces that a horizontal directional drill machine must apply to the drill pipe frequently exceed the weight of the machine itself. Therefore, a system is required to anchor the machine and resist these forces. The most common system for anchoring the drill machine comprises the use of stakes mounted on the machine body which are screwed into the ground. The stakes have flighting on their tips and are driven into the ground by applying simultaneous rotational and vertical driving forces to each stake. To drive and remove these stakes, a stakedown assembly is conventionally provided on the end of the drill machine where the drill head enters the ground.
A common stakedown assembly in the prior art includes a single drive head which is fixed in one position. This type of stakedown assembly provides a single location, predetermined by the manufacturer, at which a stake can be driven. Other stakedown assemblies, also in the prior art, have two drive heads so that two stakes can be installed into the ground for extra holding strength, or a single stake can be installed in either of the two available locations. Depending on the push-pull forces required and the texture of the ground material, however, a single stake may not be adequate to securely hold the machine in place. Several stakes may be required. The subsurface of the underlying ground may contain obstacles such as large rocks or previously buried pipes or lines which limit the locations where a stake may be installed. So, the two drive head assembly is frequently inadequate. Furthermore, the two drive head assembly is limited in the number of possible stake installation locations and suffers from the higher cost and added complexity associated with the use of dual components.
BRIEF SUMMARY OF THE INVENTION
It is an object of the invention to provide a new and improved stakedown assembly for a horizontal directional drill machine.
Another object is to provide a stakedown assembly which affords multiple position stakedown options in a simple and inexpensive construction.
The stakedown assembly of the present invention includes a tower mounted on a base plate for rotation about its vertical axis. The base plate has stake guide holes arranged in a semi-circular pattern, at equal distances from the tower. Connected to the top of the tower is a drive head which is mounted on an arm cantilevered over the semi-circle defined by the guide holes. A sliding connection allows the arm to travel vertically along the tower. A hydraulic cylinder connects the arm with the bottom of the tower. A motor on the cantilevered arm powers the drive head for rotating a stake.
The drive head can be positioned directly over each of the guide holes by rotating the tower about its axis. A locking mechanism is provided for locking the arm of the drive head in position over the desired guide hole. The cylinder is actuated to force the arm and stake downwardly. The motor is actuated to rotate the stake.
REFERENCES:
patent: 337968 (1886-03-01), Manning
patent: 3559750 (1971-02-01), Mares
patent: 3797587 (1974-03-01), Klein
patent: 3814192 (1974-06-01), Steen
patent: 3837757 (1974-09-01), Levine
patent: 3842610 (1974-10-01), Willis et al.
patent: 4105079 (1978-08-01), Schmidt
patent: 4468159 (1984-08-01), Oster
patent: 6131674 (2000-10-01), Draney et al.
Draney Robert G.
Sassor Donald C.
Spivak Dmitry I.
Volden Jeffrey S.
Brinks Hofer Gilson & Lione
Case Corporation
Lione Richard G.
Smith Scott A.
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