TABLE SAW

This application is a continuation of U.S. patent application Ser. No. 15/947,985 filed on Apr. 9, 2018, the entire content of which is incorporated herein by reference.

The present invention relates generally to power tools, and in particular to improvements for power table saws.

Table saws are commonly used power tools in the construction and wood working industries. When a saw blade of the table saw cuts a workpiece, the height and angle of the saw blade relative to the workpiece determines the depth and angle of cut into the workpiece. The height and orientation of the saw blade can be adjusted relative to a working surface of the table saw (and therefore the workpiece) through height and bevel adjustment mechanisms. Also, depending on the desired workpiece cutting operation, various components may be added or removed from the table saw to facilitate the cutting operation. Even further, the saw blade may be changed with a different saw blade depending upon the desired workpiece cutting operation or the material of the workpiece being cut.

The present invention provides, in another aspect, a table saw including a table, a spindle rotatably coupled to the table for driving a saw blade extending through an opening in the table, at least one flange plate coupled for co-rotation with the spindle for clamping the saw blade to the spindle, and an actuator movable relative to the spindle between a release position and a lockout position. In the release position, the actuator is disengaged from the spindle. In the lockout position, the actuator is engaged with the spindle or the flange plate to prevent rotation of the spindle to facilitate changing the saw blade. The table saw further includes a spring biasing the actuator toward the release position.

The present invention provides, in another aspect, a table saw including a table and a saw unit movably coupled underneath the table. The saw unit includes a spindle rotatably coupled to the table for driving a saw blade extending through an opening in the table and at least one flange plate coupled for co-rotation with the spindle for clamping the saw blade to the spindle. The table saw further includes a riving knife extending through the opening in the table and aligned with the saw blade extending through the opening, and a quick-release assembly selectively coupling the riving knife to the table. The quick-release assembly includes a mounting plate coupled to the table, a clamping plate that is movable relative to the mounting plate between a clamping position and a release position, a pin having a first end coupled for movement with the clamping plate, a handle pivotably coupled to a second end of the pin and including a cam portion engageable with the saw unit, wherein the clamping plate is movable between the clamping position and the release position in response to pivoting movement of the handle. In the clamping position, the riving knife can be clamped between the mounting plate and the clamping plate to secure the riving knife to the table. In the release position, the riving knife is releasable from the table. The table saw further includes an actuator movable relative to the spindle between a release position, in which the actuator is disengaged from the spindle, and a lockout position, in which the actuator is engaged with the spindle or the flange plate to prevent rotation of the spindle to facilitate changing the saw blade. The table saw further includes a spring biasing the actuator toward the release position.

The present invention provides, in another aspect, a table saw including a table, a saw unit movably coupled underneath the table, a riving knife extending through an opening in the table and aligned with a saw blade extending through the opening, and a quick-release assembly selectively coupling the riving knife to the table. The quick-release assembly includes a mounting plate coupled to the table, a clamping plate that is movable relative to the mounting plate between a clamping position and a release position, a pin having a first end coupled for movement with the clamping plate, and a handle pivotably coupled to a second end of the pin and having a cam portion engageable with the saw unit, wherein the clamping plate is movable between the clamping position and the release position in response to pivoting movement of the handle. In the clamping position, the riving knife can be clamped between the mounting plate and the clamping plate to secure the riving knife to the table. In the release position, the riving knife is releasable from the table. The table saw further includes a blade height adjustment mechanism operable to raise and lower the saw unit relative to the table. The blade height adjustment mechanism includes a first drive shaft defining a first rotational axis to which a first bevel gear is coupled for co-rotation, and a second drive shaft defining a second rotational axis to which a second bevel gear is coupled for co-rotation. The second rotational axis is perpendicular to the first rotational axis, and the second drive shaft is threaded to the saw unit such that rotation of the second drive shaft moves the saw unit in a direction parallel to the second rotational axis. The first and second bevel gears are meshed for transferring torque from the first drive shaft to the second drive shaft. A ratio of teeth on the second bevel gear to the teeth on the first bevel gear, respectively, is between about 0.5:1 and about 0.75:1.

The present invention provides, in another aspect, a table saw including a table and a saw unit movably coupled underneath the table. The saw unit includes a spindle rotatably coupled to the table for driving a saw blade extending through an opening in the table, and at least one flange plate coupled for co-rotation with the spindle for clamping the saw blade to the spindle. The table saw further includes a blade height adjustment mechanism operable to raise and lower the saw unit relative to the table. The blade height adjustment mechanism includes a first drive shaft defining a first rotational axis to which a first bevel gear is coupled for co-rotation, and a second drive shaft defining a second rotational axis to which a second bevel gear is coupled for co-rotation. The second rotational axis is perpendicular to the first rotational axis, and the second drive shaft is threaded to the saw unit such that rotation of the second drive shaft moves the saw unit in a direction parallel to the second rotational axis. the first and second bevel gears are meshed for transferring torque from the first drive shaft to the second drive shaft. A ratio of teeth on the second bevel gear to the teeth on the first bevel gear, respectively, is between about 0.5:1 and about 0.75:1. The table saw further includes an actuator movable relative to the spindle between a release position, in which the actuator is disengaged from the spindle, and a lockout position, in which the actuator is engaged with the spindle or the flange plate to prevent rotation of the spindle to facilitate changing the saw blade. The table saw further includes a spring biasing the actuator toward the release position.

Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

With reference to FIG. 1, a table saw 10 includes a tubular base 12, a table 14 atop the base 12 upon which a workpiece is supported, and a saw blade 18 protruding through an opening 22 in the table 14. The table saw 10 also includes a riving knife 26 positioned behind the saw blade 18 and a blade guard assembly 30 supported by the riving knife 26 for covering the top and opposite sides of the saw blade 18.

With reference to FIG. 3, the table saw 10 also includes an undercarriage 34 pivotably coupled to a bottom surface of the table 14. The undercarriage 34 includes a dust shroud 38 for directing saw dust and other debris away from the table saw 10 and a saw unit 42 supported by the dust shroud 38. The saw unit 42 includes a motor 46, a spindle 50 (FIG. 5) driven by the motor 46, and the saw blade 18, which is coupled for co-rotation with the spindle 50. The undercarriage 34 is pivotably coupled to the table 14 by a pair of pivot brackets 54 (FIG. 3), allowing the undercarriage 34 to be pivoted to various bevel angles relative to the table 14. The table saw 10 further includes a bevel angle adjustment mechanism 58 operable to adjust and selectively maintain the undercarriage 34, and therefore the saw unit 42, at a user-selected bevel angle relative to the table 14.

With reference to FIGS. 3 and 4, the table saw 10 further includes a blade height adjustment mechanism 62 operable to raise and lower the saw unit 42 relative to the table 14. The blade height adjustment mechanism 62 includes a crank 66 that is disposed in front of a front panel 70 of the base 12. The crank 66 is rotatable about a first rotational axis 74 for driving a first drive shaft 78 and a first bevel gear 82 coupled for co-rotation with the first drive shaft 78. The blade height adjustment mechanism 62 also includes a second bevel gear 86 that is intermeshed with and driven by the first bevel gear 82. The second bevel gear 86 is coupled for co-rotation with a second drive shaft 90, which is rotatable about a second rotational axis 94 that is perpendicular to the first rotational axis 74. As illustrated in FIG. 4, the second drive shaft 90 includes external threads engaged with corresponding internal threads on the saw unit 42.

With continued reference to FIGS. 3 and 4, when the second drive shaft 90 rotates about the second rotational axis 94, the saw unit 42 translates along the second drive shaft 90 in a direction parallel to the second rotational axis 94. The blade height adjustment mechanism 62 further includes a support shaft 98 (FIG. 3) parallel with the second drive shaft 90 for guiding translation of the saw unit 62. However, the support shaft 98 is cylindrical and non-threaded, permitting the saw unit 42 to slide along the support shaft 98 when the crank 66, and therefore the drive shafts 78, 90 and bevel gears 82, 86, are rotated. To adjust the height of the saw unit 42 relative to the table 14, an operator would rotate the crank 66 about the first rotational axis 74. When the crank 66 is rotated, for example, in a clockwise direction, the saw unit 42 moves upwardly relative to the table 14. In contrast, when the crank 66 is rotated, for example, in a counter-clockwise direction, the saw unit 42 moves downwardly relative to the table 14.

As shown in FIG. 4, the first (input) bevel gear 82 has a greater number of teeth than the second (output) bevel gear 86, thereby providing a gear ratio between the bevel gears 82, 86 that is less than 1:1. In other words, to achieve one complete revolution of the second drive shaft 90 and second bevel gear 86, less than one complete revolution of the first drive shaft 78 and the first bevel gear 82 is required. Specifically, the ratio of teeth on the second bevel gear 86 to the teeth on the first bevel gear 82 is between about 0.5:1 and about 0.75:1. More specifically, the ratio of teeth on the second bevel gear 86 to the teeth on the first bevel gear 82 is approximately 0.52:1. This enables the saw unit 42 to be raised and lowered relative to the table 14 with fewer rotations of the crank 66 compared to a conventional table saw.

With reference to FIGS. 5-8, the saw blade 18 is clamped between opposed flange plates 100A, 100B coupled for co-rotation with the spindle 50. As shown in FIG. 7, the flange plate 100A is axially abutted with an integral flange 102 on the spindle 50. However, the flange plate 100A may alternatively be integrally formed with the flange 102 as a single piece, as shown in FIG. 7A. In either embodiment, the spindle 50 includes a threaded end to receive a nut 104, which secures the flange plate 100B to the spindle 50 (FIG. 6). With reference to FIGS. 5 and 7, an actuator 106 is slidably supported for movement via a first bracket 110, which is fastened to the saw unit 42, relative to the spindle 50 in a transverse direction to a longitudinal axis 114 of the spindle 50. Specifically, the actuator 106 is movable between a lockout position (shown as phantom lines in FIG. 8) and a release position (shown as solid lines in FIG. 8) along an actuator axis 116 that is transverse relative to a longitudinal axis 114 of the spindle 50. The actuator 106 is accessible through the opening 22 in the table 14 when a throat plate of the table saw 10 is removed, as shown in FIG. 2. The actuator 106 is biased by a compression spring 108 (FIG. 8) away from the spindle 50 toward the release position. The actuator 106 also includes a tab 122 extending from the first bracket 110 that may be pressed by an operator of the table saw 10 to displace the actuator 106 toward the lockout position, causing a protrusion 126 of the actuator 106 to be received in one of multiple slots 130 in the flange plate 100A adjacent the spindle flange 102. In this manner, rotation of the spindle 50 may be locked to permit the table saw 10 operator to unthread the nut 104 from the spindle 50 to change or remove the saw blade 18. The actuator 106 further includes a finger 124 extending away from the actuator axis 116 against which the spring 108 abuts, as described in further detail below.

With continued reference to FIG. 8, the first bracket 110 rotatably supports the spindle 50 relative to the table 14 via bearing 129. The first bracket 110 defines a pocket 128 in which the spring 108 is at least partially positioned. As illustrated, the spring 108 is interposed between a bottom surface 132 of the pocket 128 and the finger 124 of the actuator 106. The finger 124 is abutted against a top surface 133 of the pocket 128 when the actuator 106 is in the release position, preventing further upward movement of the actuator 106. The table saw 10 further includes a second bracket 135 attached to the first bracket 110 between which the actuator 106 is held. The second bracket 135 defines a slot 137 that laterally constrains movement of the actuator 106, limiting movement of the actuator between the release position and the lockout position to translation within the slot 137 along the axis 116.

With reference to FIG. 9, the table saw 10 further includes a quick-release assembly 134 for attaching and detaching the riving knife 26, to which the blade guard assembly 30 is attached, relative to the table 14. The quick-release assembly 134 is mounted to a frame 136 of the saw unit 42. Therefore, the quick-release assembly 134, along with the attached riving knife 26 and blade guard assembly, are vertically and angularly adjustable relative to the table 14 in unison with the saw unit 42.

With reference to FIGS. 10-13, the quick-release assembly 134 includes a mounting plate 138 fastened to the saw unit frame 136 for movement therewith and a clamping plate 142 slidable along parallel fasteners 146 (FIGS. 12 and 13) anchored to the mounting plate 138 relative to (i.e., toward and away from) the mounting plate 138. The quick-release assembly 134 also includes a pin 154 having a first end 158 attached to the clamping plate 142 for movement therewith and an opposite second end 162 protruding through the mounting plate 138. The pin 154 includes a reduced-diameter section 166 (FIGS. 12 and 13) and an adjacent cylindrical section 170, which is adjacent the clamping plate 142. As illustrated in FIG. 11, the riving knife 26 includes a vertical slot 174 having a width 178 less than the diameter of the cylindrical section 170 of the pin 154 but greater than the reduced-diameter section 166, and a single aperture 182 coexistent with the slot 174 that has a nominally larger diameter than the cylindrical section 170 of the pin 154. The quick-release assembly 134 also includes a compression spring 150 biasing the pin 154 and the attached clamping plate 142 toward a release position, described in detail below, relative to the riving knife 26.

With reference to FIGS. 12 and 13, the quick-release assembly 134 further includes a handle 186 having a cam surface 190. The end 162 of the pin 154 is threaded to a barrel nut 188 within the handle, thereby pivotably coupling the pin 154 to the handle 186 about a pivot axis 194. The cam surface 190 is in sliding contact with an intermediate bracket 198 which, in turn, is stationary and mounted to the saw unit frame 136. The cam surface 190 defines a progressively changing radius of contact R between the pivot axis 194 and the bracket 198, thereby imparting translation to the pin 154 (thus causing spring 150 to compress) as the handle 186 is rotated in a direction coinciding with an increasing radius of contact R. Likewise, as the handle 186 is rotated in an opposite direction coinciding with a decreasing radius of contact R, the spring 150 rebounds, pushing the pin 154 in an opposite direction.

When the pin 154 and the attached clamping plate 142 are located in a clamping position coinciding with a relatively large radius of contact R of the cam surface 190 (FIG. 12), the cylindrical section 170 of the pin 154 is received in the aperture 182 in the riving knife 26, thereby locking the riving knife 26 to the mounting plate 138 and the saw unit frame 136. Also when the pin 154 and the clamping plate 142 are in the clamping position, the clamping plate 142 is pressed against the riving knife 26 to exert a clamping force against the riving knife 26 and the mounting plate 138. To remove the riving knife 26, the handle 186 is pivoted away from the saw unit frame 136, decreasing the radius of contact R and allowing the spring 150 to rebound and translate the pin 154 (with the attached clamping plate 142) toward the release position shown in FIG. 13. In the release position, the reduced-diameter section 166 of the pin 154 is aligned with the slot 174 and the cylindrical section 170 is displaced from the aperture 182. And, the clamping plate 142 is displaced from the mounting plate 138, thereby removing the clamping force from the riving knife 26. Thereafter, the riving knife 26 may be pulled upward and removed from the table 14. Reattachment of the riving knife 26 is done using the reverse procedure. Friction between the cam surface 190 and the intermediate bracket 198 prevents the handle 186 from inadvertently moving from the position shown in FIG. 12 coinciding with the clamping position of the pin 154 to the position shown in FIG. 13 coinciding with the release position of the pin 154.

Various features of the invention are set forth in the following claims.