Dual stage drive for power equipment

A power equipment includes a base defining an enclosure space, a table supported on the base, and a cutting assembly supported within the enclosure space below the table. The cutting assembly includes a motor having an output shaft and a dual stage drive system operably coupled to the output shaft. The output shaft defines a first axis of rotation. The dual stage drive system includes two drive stages which enable the motor of the drive system to be moved farther inward, away from the table top, which provides clearance for the incorporation of other features into and immediately below the table top.

TECHNICAL FIELD

This disclosure relates to power equipment, and particularly drive systems for driving the cutting blade of a power equipment.

BACKGROUND

Table mounted cutting tools, such as table saws, are valuable tools used for a variety of tasks, such as cross-cutting wood, and ripping large boards or panels into narrow strips. While there are a variety of table saw designs, most table saws include a base housing structure that supports a table top and a cutting assembly positioned below the table top. The table top has a substantially planar upper surface upon which workpieces may be supported.

The cutting assembly includes a circular saw blade that is mounted on an arbor with a portion of the blade extending upwardly through an opening defined in the table top. The cutting assembly also includes a motor with power train for rotating the arbor so that the cutting blade may be driven to perform cutting operations on workpieces supported on the table top. As the motor drives the cutting blade to rotate, a workpiece may be moved across the table top against the blade to allow the blade to perform cuts on the workpiece.

Traditional table saws typically utilize a single stage gear or belt drive system for coupling the drive motion of the motor to the arbor of the cutting blade, which is sufficient for most applications. However, utilizing a single stage gear or belt drive system often requires that the motor be positioned very close to the table top to provide adequate vertical cutting capacity for the blade as depicted inFIG. 4(dimension b). The close positioning of the motor in relation to the table top leaves little to no room for other features to be incorporated into or below the table top.

DESCRIPTION

The present disclosure is directed to a dual stage drive system for a power equipment. In one embodiment, the power equipment includes a base defining an enclosure space, a table supported on the base above the enclosure space and including a blade opening, and a cutting assembly supported within the enclosure space below the table. The cutting assembly includes a motor having an output shaft, a dual stage drive system operably coupled to the output shaft, and an arbor operably coupled to the dual stage drive system. The arbor is configured to retain a cutting blade with the cutting blade extending upwardly from the enclosure space through the blade opening in the table. The output shaft defines a first axis of rotation. The dual stage drive system includes a first pinion mounted on the output shaft for rotation about the first axis. A first gear is positioned in meshing engagement with the first pinion and mounted on a first shaft that defines a second axis of rotation that is substantially parallel to the first axis and offset from the first axis. A second pinion is mounted on the first shaft for rotation about the second axis. A second gear is positioned in meshing engagement with the second pinion, the second gear being mounted on a second shaft, the second shaft defining a third axis of rotation that is substantially parallel to the second axis and being positioned such that the third axis is offset from the first axis and the second axis. The arbor is connected to the second shaft for rotation about the third axis along with the second shaft.

In another embodiment, the power equipment includes a base defining an enclosure space, a table supported on the base above the enclosure space and including a blade opening, and a cutting assembly supported within the enclosure space below the table. The cutting assembly includes a motor having an output shaft, a dual stage drive system operably coupled to the output shaft, and an arbor operably coupled to the dual stage drive system. The arbor is configured to retain a cutting blade with the cutting blade extending upwardly from the enclosure space through the blade opening in the table. The output shaft defines a first axis of rotation. The dual stage drive system includes a first gear mounted on a first shaft. The first shaft defines a second axis of rotation that is substantially parallel to the first axis and is positioned such that the second axis is offset from the first axis. A pinion gear is mounted on the first shaft for rotation about the second axis, and a second gear is positioned in meshing engagement with the second pinion. The second gear is mounted on a second shaft that defines a third axis of rotation that is substantially parallel to the second axis and positioned such that the third axis is offset from the first axis and the second axis. A belt is wound around the output shaft and the first shaft for driving the first shaft about the second axis in response to the output shaft being driven about the first axis. The arbor is connected to the second shaft for rotation about the third axis along with the second shaft.

The power equipment may be any equipment having a saw blade and capable of penetrating into workpieces, such as wood, including a table saw, bevel saw, miter saw, shop saw, band saw, jig saw, circular saw, chain saw, planer, joiner, etc. The dual stage drive system includes two drive stages which enable the motor of the drive system to be moved farther inward, away from the table top, which provides clearance for the incorporation of other features into and immediately below the table top. Offsetting the motor from the arbor of the cutting blade also allows the arbor of the saw blade to be positioned closer to table top to maximize the vertical cutting capacity of the blade. Offsetting the motor from the table top also enables negative bevel angles.

FIGS. 1 and 2depict an exemplary embodiment of a power equipment10including a dual stage drive system in accordance with the present disclosure. As depicted inFIG. 1, the power equipment is a table saw assembly10and includes a base frame12, a main table14, and a cutting assembly16. The base frame12defines an enclosure space18where the components of the cutting assembly16, such as the motor20(FIG. 2), dual stage drive system22(FIG. 2), arbor24(FIG. 2), and circular saw blade26are mounted. The main table14is supported on the base frame12above the cutting assembly16and includes a generally planar upper surface that serves as a workpiece support surface. The circular saw blade26of the cutting assembly16extends upwardly through a blade opening28defined in the main table14.

Referring now toFIG. 2, an embodiment of the dual stage drive system for cutting assembly16of the table saw assembly ofFIG. 1is shown. As depicted inFIG. 2, the drive system includes a motor20, a gear housing22, an arbor24, and a circular saw blade26. The motor20comprises an electric motor and includes an output shaft with a pinion28mounted thereon the shaft. The motor20is configured to drive the output shaft P1 to rotate about a first axis26, or motor axis.

The gear housing22houses a dual gear drive in accordance with one embodiment of the present disclosure. The dual gear drive includes a first pinion28that is configured to be driven to rotate about the first axis26as the motor output shaft. The first pinion28is in turn meshed with a first gear30, which may comprise a spur gear or similar type of gear. The first gear30is supported by a first shaft for rotation about a second axis32that is parallel to and offset from the first axis26. As can be seen inFIG. 2, the second axis32is offset from the first axis26aside or toward the main table14.

The shaft of the first gear30may be supported at each end by bearings as depicted inFIG. 2. A second pinion34is attached to the shaft or to the first gear30for rotation with the first gear about the second axis32. The second pinion34is in turn meshed with a second gear36(e.g., a spur gear). The second gear36is supported by a second shaft for rotation about a third axis38that is offset from the motor axis26and the first axis32. As can be seen inFIG. 2, the third axis38is offset from the second axis32aside or toward the main table14.

The second shaft is supported in bearings for rotation about the third axis38. The third axis38also corresponds to the axis of rotation of the arbor24and the circular saw blade26. The second shaft is aligned axially with the arbor24and is connected to the arbor24in a manner that enables the arbor24to be driven to rotate about the third axis38along with the second shaft by the second gear36. In use, the motor20drives the first pinion28to rotate about the first axis26which in turn causes the first gear30to rotate about the second axis32. Rotation of the first gear30about the second axis32causes the second pinion34to rotate which in turn causes the second gear36to rotate about the third axis38. The second gear36rotates the second shaft which causes the arbor24and the saw blade26to be rotated about the third axis38.

The use of the dual gear drive enables the motor20to be offset farther below the main table than would possible with a single stage drive, such as depicted inFIG. 4. Increasing the distance (dimension b inFIG. 2) between the motor20and the main table14allows other features to be incorporated into the main table, such as a sliding table40, as depicted inFIG. 2. The sliding table40is configured to slide outwardly from the main table14in order to extend the support surface so that larger workpieces can be supported on extension table surface by fixed miter fence and to be moved toward blade for cross cut with higher accuracy than if supported by the main table.

The upper surface of the sliding table40needs to be arranged substantially in plane with the upper surface of the main table14so as not to alter the angle of the workpiece in relation to the blade and also to allow smooth movement of workpieces across the surface of the main table. To allow the upper surface of the sliding table40to be positioned in plane with the upper surface of the main table, the sliding table support42and mounting structures must be recessed below the main table14.

By utilizing the dual gear drive system ofFIG. 2, the motor20can be offset a suitable distance (dimension b) from the main table14to provide clearance (dimension c) for the mounting components42and the lower body of the sliding table40to be recessed below main table14. The dual gear drive also allows the motor20to be more offset from the arbor24. Further, the dual gear drive has smaller gears outside diameter for the same gear ratio. This enables the arbor24to be moved closer to the main table in order to maximize the vertical extension (dimension a) of the blade26through the opening in the main table.

As an alternative to the dual gear drive system ofFIG. 2, a belt/gear dual drive system may be utilized as depicted inFIG. 3. The belt/gear dual drive system includes a belt44that is looped around the output pulley mounted on a shaft46of the motor20at one end and looped around a pulley mounted on a shaft48at the other end. A pinion50on the pinion shaft48is meshed with a gear52. The gear52is supported on a shaft54that is connected to the arbor24. The belt/gear dual drive ofFIG. 3enables the motor20to be offset a significant distance below the main table14and even to be positioned below the gears and/or the blade if desired. The dual belt/gear drive also has smaller gears outside diameter for the same gear ratio. This enables the arbor24to be moved closer to the main table in order to maximize the vertical extension (dimension a) of the blade26through the opening in the main table similar to the dual gear system ofFIG. 2.