Cutlery – Cutting tools – Saw
Reexamination Certificate
1998-07-10
2001-05-15
Peterson, Kenneth E. (Department: 3724)
Cutlery
Cutting tools
Saw
C030S392000, C030S375000, C083S829000
Reexamination Certificate
active
06230411
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to hand-held electric saws. More particularly, the present invention relates to blade guide systems for reciprocal saws such as jigsaws.
BACKGROUND OF THE INVENTION
Electrically powered jigsaws, also known as saber saws, are well known in the art. A principle advantage of jigsaws over other types of hand-held saws such as circular saws or band-type saws is the ability to make curved cuts along relatively short radiuses. Consequently, jigsaws are particularly useful in performing tight scrolling cuts to cut curves into a work piece.
A conventional jigsaw typically includes an electric motor contained within a housing, and a shoe positioned beneath the housing. The shoe includes a bottom surface adapted to slide or ride along the top surface of a work piece. An open-ended slot is formed at a front end of the shoe. A straight, bayonet-type saw blade extends downward from the housing through the front slot. A leading edge of the blade includes a plurality of teeth that face in a forward direction toward the front of the shoe. In use, the blade is reciprocated in a generally up-and-down direction by the motor. As the blade is reciprocated, the jigsaw is manually advanced in a forward direction such that the teeth of the blade cut into a work piece. As the blade cuts into the work piece, the bottom surface of the shoe rides over the top of the work piece.
Some jigsaws are capable of producing an orbital blade motion. Such a motion has a rectilinear component of a generally up-and-down nature, and fore-and-aft motion advancing the cutting blade into the work piece. Typically, the blade advances on the cutting stroke, which is conventionally in the upstroke on most saws.
Commonly, jigsaws are used to provide perpendicular cuts through a work piece. However, frequently, a user may desire to provide a bevel cut through a work piece. A bevel cut is a cut at an angle other than perpendicular such as angles that are offset 15°, 30° or 45° with respect to perpendicular. To achieve a bevel cut with a conventional jigsaw, the motor housing and the blade are pivoted relative to the jigsaw shoe. Specifically, the housing is pivoted about a front-to-rear longitudinal axis. By pivoting the housing relative to the shoe, the blade can be aligned at a desired oblique angle relative to the bottom surface of the shoe. Typically, the housing is retained in the desired orientation relative to the shoe by a clamp mechanism. When the clamp mechanism is tightened, relative movement between the housing and the shoe is inhibited. When the clamp mechanism is loosened, the housing and the shoe can be pivoted relative to one another. It is desirable for the clamping mechanism to be easy to operate. It is also desirable for the clamping mechanism to effectively hold the shoe in the desired orientation without undesired loosening.
As described above, jigsaws are commonly used to make tight radial cuts. However, in making a tight radial cut, it is common for the reciprocating blade to twist thereby making it difficult to control the cutting path of the blade. To resist twisting of the blade, some jigsaws have utilized grooved rollers that support a rear portion of the blade. A grooved blade roller guide will typically prevent the back portion of the blade from moving laterally across the roller surface, but is of limited assistance in stabilizing the blade against the twisting action encountered during scroll cutting. To resist twisting of the blade, it is desirable to have a blade guide positioned in close proximity to the work piece. To provide lateral support in close proximity to a work piece, U.S. Pat. Nos. 2,996,089 and 3,303,861 each discloses a jigsaw having a fixed blade guide connected to the jig saw shoe. Such designs are problematic because the fixed blade guides inhibit pivoting between the housing and the shoe.
SUMMARY OF THE INVENTION
A general aspect of the present invention relates to a blade guide for providing lateral support to a reciprocating saw blade.
Another general aspect of the present invention relates to a blade guide adapted to be positioned in close proximity to a work piece being cut.
A further aspect of the present invention relates to a blade guide connected to a jigsaw shoe that allows a motor housing and blade of the jigsaw to be pivoted relative to the shoe.
Still another aspect of the present invention relates to a blade guide that is pivotally connected to a shoe of a jigsaw.
An additional aspect of the present invention relates to a blade guide that is pivotally moveable about an axis that extends longitudinally along a jigsaw shoe.
The present invention also relates to a jigsaw including a base, a housing pivotally movable relative to the base about a first axis that extends longitudinally along the base, and a motor positioned within the housing. The jigsaw also includes a blade coupled to the motor by a drive mechanism adapted for reciprocating the blade in an up-and-down motion. The blade is laterally supported by a blade guide connected to the base that is pivotally movable about the first axis. When the housing is pivoted relative to the base about the first axis, the blade guide also pivots about the first axis to inhibit binding between the blade and the blade guide.
The present invention additionally relates to a jigsaw including a base, a housing pivotally movable relative to the base, and a motor positioned within the housing. The jigsaw also includes a blade coupled to the motor by a drive mechanism adapted for reciprocating the blade in an up-and-down motion. A cutting angle of the blade relative to the base can be adjusted by pivoting the housing relative to the base. A blade guide connected to the base provides lateral support to the blade to inhibit twisting of the blade during cutting operations. The jigsaw also includes means for pivoting the blade guide relative to the base when the cutting angle of the blade is adjusted relative to the base.
The present invention further relates to a shoe for a jigsaw. The shoe includes a base structure having a bottom surface adapted to engage a work surface. The base structure defines an open-ended front slot that extends generally longitudinally along the base. The shoe also includes a blade guide connected to the base structure for providing lateral support to a saw blade. The blade guide is positioned proximate the front slot and is pivotally movable relative to the base structure about a pivot axis that extends longitudinally along the base structure. Because the blade guide is connected to the base structure adjacent to the front slot, the blade guide provides lateral support to the saw blade in close proximity to the work surface intended to be cut.
A variety of advantages of the invention will be set forth in part in the description that follows, and in part will be apparent from the description, or may be learned by practicing the invention. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed.
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Etter Mark A.
Kriaski John R.
Wall Daniel P.
Merchant & Gould P.C.
Peterson Kenneth E.
Porter-Cable Corporation
Tran Kim Ngoc
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