Cutlery – Cutting tools – Saw
Reexamination Certificate
1999-08-13
2001-10-16
Rada, Rinaldo I. (Department: 3724)
Cutlery
Cutting tools
Saw
C030S374000
Reexamination Certificate
active
06301789
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to circular saws, and, more particularly, to a circular saw having an improved line-of-sight for the operator.
A typical circular saw includes a housing supporting a motor which rotatably drives a saw blade. The housing also forms a blade guard covering the upper portion of the saw blade. A shoe plate supports the circular saw on the surface of a workpiece. The circular saw also includes a main operator's handle mounted on the motor housing and an auxiliary handle supported on the housing or the shoe plate. Due to the arrangement of the components of the circular saw, only a portion of the outward face of the saw blade is generally visible as the saw blade cuts the workpiece.
During cutting operations, the operator typically grasps the main handle with one hand (the right hand) and grasps the auxiliary handle with the other hand (the left hand). In an optimal cutting position, the operator holds the circular saw so that the circular saw is centered relative to the operator's body. However, to view the saw blade as the saw blade cuts the workpiece, the operator must stand in a position so that the outward face of the saw blade is visible. To do so, the operator must lean over the outward face of the saw blade (generally on the right side of the circular saw).
In some circular saws, the shoe plate is pivotally connected to the housing so that the angle at which the saw blade cuts the workpiece (the bevel angle) is adjustable. Typically, the circular saw includes an indicator located toward the front of the circular saw and indicating the bevel angle of the saw blade.
In some constructions, the indicator faces the front of the circular saw, away from the operator. To view such a front indicator, the operator must hold the circular saw so that the front of the circular saw faces towards the operator.
In some other constructions, the indicator faces towards one side of the circular saw (the left side, opposite the outward face of the saw blade) and is generally parallel with the edge of the shoe plate. To view such a side-facing indicator, the operator must hold the circular saw so that the side of the circular saw faces towards the operator.
SUMMARY OF THE INVENTION
One problem with the above-described circular saw is that, to view the saw blade as the saw blade cuts the workpiece, the operator must be in a position to view the outward face of the saw blade below the blade guard. The operator must lean across their body to the outward side of the circular saw to view the saw blade. In this position, the operator is not in the optimal cutting stance, centered behind the circular saw, and is not holding the circular saw in the optimal cutting position. This position is awkward, and the operator's stance may not be balanced. Also, because the operator's body weight is not centered behind the circular saw, the operator has less precise control of the circular saw. In addition, the operator is in a relatively exposed position and may be hit by debris cut by the saw blade.
One problem with the above-described circular saws including a bevel angle adjustment assembly is that, in order to adjust the bevel angle, the operator must move from the cutting position, in which the saw blade is visible, to a position in which the bevel angle indicator is visible and in which the saw blade is no longer visible. The operator must then move back to the cutting position to resume cutting operators. These movements decrease the operator's efficiency during combined straight and bevel cutting operations.
Another problem with the above-described circular saw including a bevel angle adjustment assembly is that, as the housing is moved relative to the shoe plate to change the bevel angle of the saw blade, the upper blade guard is moved outwardly and downwardly toward the surface of the workpiece. In a beveled cutting position (i.e., 45° bevel angle), the upper blade guard obscures the operator's view of the outward face of the saw blade as the saw blade cuts the workpiece. In order to view the saw blade, the operator lean further outwardly and downwardly, increasing the awkwardness and imbalance in the operator's stance during cutting operations.
The present invention provides a circular saw with an improved line-of-sight to alleviate the problems with the above-described circular saws. The invention provides a circular saw in which the operator can view the saw blade as it cuts the workpiece while maintaining a comfortable and balanced stance and while holding the circular saw in an optimal cutting position. The components of the circular saw are arranged so that the operator can view the inward face of the saw blade (the face of the saw blade facing a substantial portion of the circular saw). The operator can remain in a centered behind the circular saw during cutting operations.
Also, the present invention provides a circular saw including a bevel angle adjustment assembly having a bevel angle indicator which is visible to the operator while the operator is in the optimal cutting stance with the circular saw in the optimal cutting position. Preferably, the bevel angle indicator is visible to the operator generally along the operator's line-of-sight of the saw blade.
One advantage of the present invention is that, while viewing the saw blade as it cuts the workpiece, the operator can maintain the optimal cutting stance and hold the circular saw in the optimal cutting position. The operator can thus maintain a comfortable and balanced stance, have more precise control of the circular saw during cutting operations, and be less exposed to debris. Also, the addition of the air flow directing means in the area of the operator's line-of-sight controls the flow of debris cut by the saw blade, further reducing the operator's exposure to this debris.
Another advantage of the present invention is that, because the bevel angle indicator is visible to the operator in the optimal cutting stance and with the circular saw in the optimal cutting position, the operator can adjust the bevel angle of the saw blade while maintaining the optimal stance and cutting position. This increases the efficiency of combined straight and bevel cutting operations.
A further advantage of the present invention is that, during bevel cutting operations (i.e., with the saw blade in a 45° bevel angle position), the operator's line-of-sight of the saw blade as it cuts the workpiece is not obscured and does not require the operator to adjust their stance.
Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings.
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Brault Richard P.
Hessenberger Jeffrey C.
Holly Jeffrey S.
James Thomas P.
Wattenbach Brian P.
Michael & Best & Friedrich LLP
Milwaukee Electric Tool Corporation
Rada Rinaldo I.
Tran Kim Ngoc
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