Gerhard Josef Karl Weusthof
John Ka Ki Chan
Eastway Fair Company Ltd.
Boyer D. Ashley
Brinks Hofer Gilson & Lione
A saw such as a chop saw, a circular saw, a compound miter saw or a sliding compound miter saw having a rotatable saw blade is provided with a laser arbor alignment system. The laser arbor may include a power generator that generates power as the saw blade and the laser arbor are rotated by a spindle. The generator may include a stator comprising an electrical magnet or a permanent magnet mounted on a fixed portion of the saw. The other portion of the generator is a rotor comprising a coil that is rotated with the laser arbor to generate power for the laser. Power may also be provided to the laser by slip ring contacts from a stationary source to the laser arbor.
1. Field of the Invention
The present invention relates to a saw having a light source alignment system that does not require internal batteries to power the light source.
2. Background Art
Miter saws, portable circular saws, radial arm saws, chop saws, and compound saws are used to precisely cut wood and other materials. For example, miter saws and compound saws are used to cut baseboards, crown moldings, cove moldings, and a wide variety of trim pieces and structural members to exact dimensions. Such circular saws generally have a blade that is rotated at a high rate of speed to cut workpieces. The blade is guarded by a retractable blade guard that covers the saw blade but is retracted as the blade is brought into contact with a workpiece. The workpiece is retained on a base and a turntable that, in conjunction with a fence, are used to position the workpiece to be cut by the saw.
Before cutting, workpieces are generally marked with a pencil at the intended cut location according to precise measurements to assure accuracy. A common problem with these types of saws is that it takes considerable skill and attention to consistently align the workpiece with the saw blade so that the edge of the saw blade cuts the workpiece at the desired location. With prior art saws, it has not been possible to know if the saw alignment is proper until the saw begins to cut the material. The workpiece may be ruined if it is not set up at the correct orientation when the saw blade contacts the workpiece.
A laser arbor for a circular saw has been proposed in U.S. Pat. No. 5,862,727 to Kelly. The Kelly patent discloses the use of a semiconductor laser arbor for a circular saw that is actuated by a centrifugal switch and directs a line of laser beam on a workpiece. The Kelly patent discloses a battery powered laser light source. One problem with reliance upon batteries is that the semiconductor laser light source draws substantial power from the batteries to illuminate the laser, resulting in limited battery life and requiring frequent battery changes. Similarly, U.S. Pat. No. 6,035,757 to Caluori et al. discloses a similar semiconductor laser light beam alignment device for a circular saw having a focusing lens that causes the laser beam to be directed to the blade cut line. The Caluori patent likewise relies upon a battery power source that is carried by the laser arbor. This system has the same problem of limited battery life as the Kelly patent.
The assignee of this application has marketed a battery power laser alignment device which is described in copending U.S. patent application Ser. No. 09/860,898 entitled Miter Saw Having a Light Beam Alignment System which is incorporated by reference herein for general background purposes.
Applicants have solved the battery life problem by their development of a laser alignment system that utilizes a power source external to the laser arbor.
According to one aspect of the present invention, a miter saw (or other circular saw) is provided that includes a motor with a spindle to which a blade is secured and rotated by the motor to cut a workpiece that is disposed on a turntable or saw table. The motor is part of a saw head assembly that is supported relative to the table by an arm. A laser or other directed light source (hereinafter referred to as laser or light source ) is mounted in a laser arbor housing that is secured to the spindle and rotated by the motor along with the blade. The light source emits a narrow beam of light from the housing to a location adjacent to the blade for checking the alignment of the blade with the workpiece. Power for the light source is provided by a source located outside the laser arbor housing.
The invention may also be defined as a laser arbor for a circular saw having a spindle that rotates the saw blade relative to a non-rotating portion of the saw. The laser arbor comprises a LED laser light and a circuit connected to the laser for providing power to the laser. The circuit provides power from a voltage source that includes a portion secured to the non-rotating portion of the saw.
According to another aspect of the invention, the circuit of the laser arbor for a circular saw may further comprise a generator having a rotor associated with the spindle and a stator associated with the non-rotating portion of the saw. Electrical energy is generated as the spindle rotates the rotor relative to the stator.
According to another aspect of the invention, the laser arbor for a circular saw may have an inductively coupled power source. The inductive power source may comprise a first induction coil inside the laser arbor that rotates with the arbor and a second induction coil mounted near the arbor that induces voltage in the first coil. The first induction coil is electrically connected to a power conditioning circuit that provides power directly to the light source. According to another aspect of the invention, the light source may be a LED laser.
Alternatively, the circuit may comprise a power source electrically connected by slip ring contacts that establish electrical contact between the power source and the circuit. The slip ring contacts may comprise a first set of contacts that rotate with the spindle and a second set of contacts that are stationary and contact the first set of contacts. The circuit further comprises a power conditioning circuit that provides power within a predetermined voltage range to the laser.
These and other aspects of the invention and advantages of the invention over the prior art will be better understood in view of the attached drawings and following detailed description provided below.
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The saw 10 shown in the illustrated embodiment is a sliding compound miter saw having a miter angle adjustment mechanism 38 and a tilt adjustment mechanism 40. While the illustrated embodiment is of a sliding compound miter saw, the invention is equally applicable to other types of circular saws such as a simple miter saw, a compound miter saw, a chop saw, portable circular saw, or radial arm saw. The saw head assembly 24 is pivotally connected to the arm 20 and includes a spring (not shown) for biasing the saw head assembly 24 normally out of engagement with the workpiece 18.
When an operator is ready to make a cut with the saw 10, the operator grips the handle 32, depresses the trigger causing the circular saw blade 12 to rotate, and pulls it down toward the workpiece 18. The miter angle adjustment mechanism 38 permits the turntable 14 to rotate relative to the base 13 to change the miter angle of cut. The tilt adjustment mechanism 40 allows the saw head assembly 24 to be pivoted to adjust the inclination of the blade 12 relative to the supporting table 15.
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In each of the embodiments described above with reference to
A power conditioning circuit may be provided by a circuit board 96 secured to the washer or could be built-in as part of laser modules. In
While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.