Woodworking – Special-work machine – Tree delimbing
Reexamination Certificate
2000-05-16
2002-06-18
Bray, W Donald (Department: 3725)
Woodworking
Special-work machine
Tree delimbing
C144S343000, C212S231000, C212S347000, C414S023000, C414S718000
Reexamination Certificate
active
06405770
ABSTRACT:
FIELD OF THE INVENTION
This invention is directed toward an improved tree delimber.
The invention is more particularly directed toward an improved delimber that is, in part, of modular construction so that the delimber can be constructed with one of several different boom drive means and one of two types of booms depending on the requirements of the delimber operator. The invention is also directed toward an improved delimber having the boom drive means operated by a variable displacement hydraulic motor to improve the range of operation of the delimber. The invention is further directed toward an improved delimber having improved cable boom drive means with hydraulic tensioning means for the cable or cables employed in the drive means.
BACKGROUND ART
Delimbers presently are constructed in several different versions. Some delimbers have cable drives for driving the delimbing boom and some have chain drives. Some delimbers employ a single section or mono boom and others employ a multi-section or telescopic boom. Because of the different versions of delimbers used, it is expensive for a manufacturer to provide a full range of delimbers and many do not.
Delimbers are also presently constructed to employ a fixed displacement hydraulic motor to operate the cable or chain drives which move the boom. This arrangement is relatively simple and inexpensive. The hydraulic motor is sized to have the delimber able to handle the size of the tree to be normally harvested and is a compromise in the power required to lift the tree and the speed required to delimb it. Because of the compromised design, the delimber is slow in picking up and handling trees larger than the normal size to be delimbed. In efforts to increase the speed of operation of the delimber when handling large trees, the operator often increases the operating pressure of the hydraulic motor over its designed limit and this can lead to failure of the motor.
Delimbers that employ cable boom drive means sometimes fail due to stress. This is, in part, due to the fact that the cables are not long enough to handle the loading. The cables can also fail if they are not properly tensioned. The cables stretch during use and it is necessary to frequently stop operation of the delimber to properly retension the cables.
SUMMARY OF THE INVENTION
It is the purpose of the present invention to provide a delimber that is, in part, of modular construction so that different versions of a delimber may be more inexpensively manufactured. It is also a purpose of the present invention to provide a delimber which, due to its modular construction, is easier to repair.
It is another purpose of the present invention to provide improved boom drive means which allows the delimber to more easily handle and delimb larger than normal trees encountered in tree harvesting operations.
It is yet another purpose of the present invention to provide means for strengthening cable boom drive means in delimbers by employing longer cables. It is also a purpose of the present invention to provide means for quickly and easily tensioning cables employed in a cable boom drive means on a delimber without having to frequently halt operation of the delimber.
The present invention is directed toward a delimber of the type having a boom slidable through a carriage, the carriage having gripping means at the front end to hold the tree, the front end of the boom having a delimbing head to delimb the tree. While the tree is held by the gripping means on the carriage, the boom is moved forwardly relative to the carriage to have the delimbing head delimb the tree.
The improvements in the delimber of the above type, in one embodiment of the invention, are related to providing a basic delimber some components of which are interchangeable to provide variations of the basic delimber depending on the buyer's requirements. The basic delimber will have a standard base and a standard carriage fixed to the base. However the carriage will be able to mount either a mono boom or a telescopic boom depending on the buyer's requirements. The drive means for the boom, mounted on the carriage, can also be changed depending on the buyer's requirements. Thus many variations of the basic delimber can be easily manufactured.
The delimber has improved boom drive means in the form of a drive module detachably mounted on the carriage. Variations of the drive module are constructed depending on the type of drive desired for the boom. Drive modules for a single cable drive system; a double cable drive system; or a chain drive system can be provided. The buyer selects any one of the various drive modules, each of which fits in the same mounting area on the carriage. The manufacture simply installs the required module in the standard carriage when manufacturing the delimber. The selected drive module is easily replaced with the same type of module making servicing of the delimber simple and inexpensive.
In accordance with another embodiment of the invention, the delimber can be provided with a strengthened cable boom drive means. The strengthened cable drive means doubles back the drive cables using guide pulleys at the ends of a mono boom. This requires the use of longer cables. However, the use of longer cables allows the cable drive means to handle impact stresses better and thus increases the life of the drive means.
At least one of the ends of each cable employed in the cable boom drive means can be provided with a hydraulic tensioner for maintaining the cable tight.
In accordance with a further embodiment of the present invention, there is provided a variable displacement hydraulic motor for operating the boom drive means. The motor allows the delimber to both more quickly delimb trees and to more easily handle larger than normal trees. The variable displacement motor, when operating at low displacement, operates at high speed for fast delimbing. With the motor operating at a higher displacement, the motor has more torque and thus is able to more easily handle larger trees. Since variable displacement motors normally operate at higher speeds than fixed displacement motors, they are employed with a gear box to provide the normal speed of operation required of the delimber.
The invention is particularly directed toward a delimber having a base; a carriage mounted on the base; a boom slidably mounted through the carriage; a drive module detachably connected to the carriage; drive means in the drive module; and drive transfer means connected between the drive means and the boom for moving the boom relative to the carriage.
The invention is also particularly directed toward a delimber having a base, a carriage mounted on the base; a boom slidably mounted through the carriage; drive transfer means for moving the boom relative to the carriage; and a variable displacement hydraulic motor for operating the drive transfer means.
The invention is further directed toward a delimber having a base, a carriage mounted on the base; a boom slidably mounted through the carriage; cable drive means for moving the boom relative to the carriage; at least one end of each cable in the cable drive means connected to a hydraulic tensioner on the delimber.
The invention is further directed toward a delimber having a base, a carriage mounted on the base; a mono boom slidably mounted through the carriage; cable drive means for moving the mono boom relative to the carriage; the cable drive means having at least one cable fixed at one end to the carriage, the cable passing over a pulley on each end of the mono boom and fixed at its other end to the carriage.
REFERENCES:
patent: 3227295 (1966-01-01), Hamilton et al.
patent: 4226270 (1980-10-01), Sturtz, Jr. et al.
patent: 4276918 (1981-07-01), Sigouin
patent: 5568829 (1996-10-01), Crawford et al.
patent: 6062793 (2000-05-01), Isley
Bellefeuille Alain
Camirand Martin
Jeanson Bertrand
Bray W Donald
Denharco Inc.
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