Hand-held cutting tool for cutting fiber

Details Hand-held cutting tool for cutting fiber Hand-held cutting tool for cutting fiber

1999-11-08

2001-06-26

Ostrager, Allen (Department: 3725)

Abrading

Frame or mount

Portable abrader

C030S228000

Reexamination Certificate

active

06250998

ABSTRACT:

TECHNICAL FIELD
The present invention relates to a hand-held tool for cutting fibercement siding used in the construction of buildings.
BACKGROUND OF THE INVENTION
The exteriors of houses and other types of buildings are commonly covered with siding materials that protect the internal structures from external environmental elements. The siding materials are typically planks or panels composed of wood, concrete, brick, aluminum, stucco, wood composites or fiber-cement composites. Wood siding is popular, but it is costly and flammable. Wood siding also cracks causing unsightly defects, and it is subject to infestation by insects. Aluminum is also popular, but it deforms easily, expands and contracts in extreme climates and is relatively expensive. Brick and stucco are also popular in certain regions of the country, but they are costly and laborintensive to install.
Fiber-cements siding (FCS) offers several advantages compared to other types of siding materials. FCS is made from a mixture of cement, silica sand, cellulose and a binder. To form FCS siding products, a liquid fiber-cement mixture is pressed and then cured to form FCS planks, panels and boards. FCS is advantageous because it is non-flammable, weather-proof, and relatively inexpensive to manufacture. Moreover, FCS does not rot or become infested by insects. FCS is also advantageous because it may be formed with simulated wood grains or other ornamental designs to enhance the appearance of a building. To install FCS, a siding contractor cuts the panels or planks to a desired length at a particular job site. The siding contractor then abuts one edge of an FCS piece next to another and nails the cut FCS pieces to the structure. After the FCS is installed, trim materials may be attached to the structure and the FCS may be painted.
Although FCS offers many advantages over other siding materials, it is difficult and expensive to cut. Siding contractors often cut FCS with a circular saw having an abrasive disk. Cutting FCS with an abrasive disk, however, generates large amounts of very fine dust that creates a very unpleasant working environment Siding contractors also cut FCS with shears having opposing blades, as set forth in U.S. Pat. No. 5,570,678 and U.S. Pat. No. 5,722,386 which are herein incorporated by reference. Although the shears set forth in these patents cut a clean edge in FCS without producing dust, many siding contractors prefer to use a hand-held tool because they are accustomed to cutting siding with hand saws. Therefore, in light of the positive characteristics of FCS and the need for a hand-held cutting tool, it would be desirable to develop a hand-held cutting tool that quickly cuts clean edges through FCS without producing dust.
To meet the demand for a hand-held FCS cutting tool, the present inventors developed a hand-held tool with a reciprocating cutting blade (the “original hand held-tool”). The original hand-held tool had a motor-unit, a drive assembly coupled to the motor-unit to generate a reciprocating motion, and a blade set with a moving blade between first and second stationary fingers. The motor-unit was a 1046-90 Black and Decker ® electric drill motor, and the drive assembly was a shear head manufactured by Kett Tool Co. of Cincinnati, Ohio. The moving blade was coupled to the Kett shear head to reciprocate between the first and second fingers. Additionally, the first and second fingers were spaced apart by 0.250 inches, and the cutting blade had a thickness of 0.185-0.200 inches. The sides of the cutting blade were accordingly spaced apart from the fingers by 0.025-0.0325 inches.
In the operation of the original hand-held tool, the fingers were placed on an FCS workpiece and the moving blade was driven. from an open position below the workpiece to a closed position in the gap between the first and second fingers. As the blade moved from the open position to the closed position, it sheared the workpiece along both sides of the blade to form a cut in the workpiece approximately as wide as the gap between the first and second fingers. An operator would accordingly push the tool as the blade reciprocated between the open and closed positions to cut the workpiece.
One drawback of the original hand-held tool, however, was that the drive assembly and the motor-unit were subject to premature failure. One possible solution for reducing premature failure of the hand-held tool was to use stronger materials in the drive mechanism. Yet, using stronger materials would require more expensive metals that would increase the cost of the tools. Another possible solution for the original hand-held tool was to increase the size of the components of the motor unit and the drive mechanism. Using larger components, however, would increase the weight of the tools making them more difficult to handle. In addition to these constraints, cutting FCS without dust presents many challenges that are not present in other materials because FCS is a relatively brittle material that tends to crack along rough edges and unpredictable paths. As such, FCS cannot be cut with a thin blade unless it is in an opposing shear like those disclosed in U.S. Pat. Nos. 5,722,386 and 5,570,678. Thus, it would be desirable to develop a hand-held cutting tool that cuts a clean edge in FCS and is not subject to premature failure.
SUMMARY OF THE INVENTION
The present invention is an apparatus for cutting fiber-cement siding. A fiber-cement siding cutting tool in accordance with the invention may have a hand-held motor unit with a housing, a motor inside the housing, and a switch operatively coupled to the motor to selectively activate the motor. A head having a casing may be attached to the housing of the motor unit. The head may also have a reciprocating drive assembly coupled to the motor.
The hand-held cutting tool also has a blade set with first and second fingers attached to either the casing or the motor housing, and a reciprocating cutting member between the first and second fingers. The first finger may have a first guide surface and a first interior surface. Similarly, the second finger may have a second guide surface and a second interior surface. The first and second guide surfaces are preferably in a common plane, and the first and second interior surfaces are spaced apart from one another by a gap distance. The reciprocating cutting member of the blade set has a body with a first width approximately equal to the gap distance and a blade projecting from the body. The blade has a first side surface facing the first interior surface of the first finger, a second side surface facing the second interior surface of the second finger, and a top surface. The first side surface of the blade is preferably spaced apart from the first interior surface of the first finger by 0.040-0.055 inches for cutting ¼ inch and {fraction (5/16)} inch thick fiber-cement siding. Similarly, the second side surface of the blade is spaced apart from the second interior surface of the second finger by 0.040-0.055 inches. The distance between the first and second side surfaces of the blade and the first and second fingers, respectively, may be approximately 13%-22% of the thickness of the fiber-cement siding workpiece.
The top surface of the blade may also have a width less than the first width of the body. For example, the top surface of the blade may be between 0.140 and 0.165 inches, and more preferably between 0.160 and 0.160 for cutting ¼ inch and {fraction (5/16)} inch thick fiber-cement siding. The top surface may also have a curvature concave with respect to the first and second guide surfaces of the first and second fingers.
In operation, the drive assembly is operatively coupled to the reciprocating member to reciprocate the blade into and out of the gap between the fingers. As the drive assembly moves the blade into the gap between the fingers, the top surface of the blade and the straight guide surfaces of the fingers shear the fiber-cement siding.


REFERENCES:
patent: 3693254 (1972-09-01), Salonen
patent: 4007523 (1977-02-01), Bianc

Affiliated with

Also associated with

Rating

Hand-held cutting tool for cutting fiber does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Hand-held cutting tool for cutting fiber, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Hand-held cutting tool for cutting fiber will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2503178