Excavating – Ditcher – Having endless digger
Reexamination Certificate
2000-08-09
2001-07-31
Novosad, Christopher J. (Department: 3671)
Excavating
Ditcher
Having endless digger
C037S363000, C037S367000
Reexamination Certificate
active
06266900
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to walk-behind trenching machines (“trenchers”) and in particular to a backfill blade attachment that enables such a trencher, after a trench has been dug and the invention then mounted on the trencher, to refill the trench that has been dug.
DESCRIPTION OF THE PRIOR ART
Machines for digging trenches have been use for many years. They are designed either to be towed by a tractor (or some other vehicle) or are self-propelled. In either case, a continuous chain loop fitted with extending teeth, rotates on a power driven roller boom to dig the trench. Trenching machines typically are designed so as to deposit dirt from the trench on one side of the trench. The trenchers are used for utility lines of various kinds such as water, gas, electrical or communications cables and sewer systems. When a trench has been dug and the cable placed therein, the trench is usually refilled manually or by a separate tractor fitted with a front or rear mounted blade.
Walk-behind trenchers, all of which are self-propelled, are substantially smaller than tractor mounted or tractor pulled trenchers. Walk-behind trenchers are used frequently in residential construction and in a variety of other tasks where use of larger duty trenchers is neither necessary nor practical. At present, walk-behind trenchers seldom, if ever, are fitted with a means to refill the trench. In the material that follows, it should be noted that the operator of a walk-behind trencher digs the trench by guiding the trencher to his rear. Use of the term “walk-behind”, therefore, is somewhat of a misnomer.
Elaborate filler attachments for trenchers are described, for example, in U.S. Pat. Nos. 3,807,067, 3,908,292 and 5,479,728. These patents describe the use of a drag conveyor or a horizontally mounted auger that moves dirt laterally to refill the trench, and also could include a tamper. U.S. Pat. No. 5,526,590 describes a vibrating compactor wherein a blade is used for backfilling. The backfilling attachment is linked so as to be movable and includes two blades that are set as wings on either side of the compactor. The device includes hydraulic cylinders to raise and lower the blade.
A need exists for an efficient, rugged, simple and relatively light weight device that can be quickly and easily installed on walk-behind trenchers to refill the trenches dug by them.
SUMMARY OF THE INVENTION
After a trench has been dug, this discovery provides a means whereby a backfill blade assembly, which can be installed on a walk-behind trencher at the free end of the roller boom/digger chain assembly by using only a slidable mounting sleeve and a stabilizing bar, enables the trencher under its power to refill the trench.
This attachment, in the preferred embodiment, is well suited for use with all walk-behind trenchers manufactured or sold in the United States, including those of the manufacturer believed to have far and away the largest market share of walk-behind trencher sales. All walk-behind trenchers have a restraining bar extending over the digger chain. This restraining bar is an integral part of the roller boom/digger chain assembly, such assembly is often hereinafter referred to as the “roller boom digger”. The blade utilized in this invention, at its front, is assembled by a slidable coupling with the restraining bar. An adjustable stabilizing bar is used so that the back end of the blade is also affixed to the trencher. The blade assembly, which typically is disposed at about a 35 degree angle to the longitudinal axis of the trencher, is held in place by mounting one end on the restraining bar and the other end on the frame of the trencher.
In use, then, after the trench has been dug and after placement in the trench of the intended pipe, wire or cable, rotation of the chain is disengaged, the roller boom digger is raised so as to be substantially parallel with the ground, and the backfill blade assembly of this invention is mounted to the free end of the roller boom digger. The operator, then, leaving the digger chain disengaged so that is remains stationary, changes the direction of the trencher to forward. This invention, acting as an extension of the roller boom digger, is used to push the recently dug dirt disposed along the edge of the trench back into the trench as the trencher moves forward. The hydraulic system of the trencher which lowers the boom for purposes of digging is used to set the height of the boom, in relationship to the ground, at the most advantageous essentially horizontal position for pushing the dirt back into the trench.
Accordingly, there are several primary objects or purposes of this invention. They are as follows:
1. To provide a method for backfilling a trench whereby the same power sources used to dig the trench can, through installation of a backfill blade assembly on the trencher, be used to push the dirt disposed along the side of the trench back into the trench.
2. To provide a backfill blade assembly capable of ready adjustment so as to be usable with walk-behind trenchers of different sizes that may be required for digging trenches of different depths and widths.
3. To make mounting and dismounting of the backfill blade assembly onto and off the trencher, as the case may be, so easy and quick that anyone capable of operating the trencher can accomplish the task with a minimum of effort.
These and other objects will become readily apparent with reference to the drawings and following description:
REFERENCES:
patent: 3807067 (1974-04-01), Cloud
patent: 3908292 (1975-09-01), Harris
patent: 5479728 (1996-01-01), Deken et al.
patent: 5526590 (1996-06-01), Palm et al.
patent: 6163987 (2000-12-01), Schommer
Casey, Esq. Donald
Novosad Christopher J.
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