NZ520648A - Bevel adjustment mechanism for a compound miter saw - Google Patents

Abstract

A miter saw (10) including a base (12), a turntable (14) rotatably mounted to the base having a planar upper surface, a fence assembly (26) affixed to the base, a saw assembly (46) including an elongate arm (54) having a fixed end pivotally attached to the turntable, a distal end forming a handle (60) and a central region therebetween, a motor assembly disposed on the elongate arm, the motor assembly including a rotary spindle supporting a cutting disk (32) and a motor operatively connected to the rotary spindle, and a bevel adjustment mechanism (40) for adjusting the angle of inclination of the cutting disk relative to the turntable upper surface (28). The bevel adjustment mechanism includes a first knuckle (44) for adjusting the angle of inclination of the cutting disk about a tilt axis (48), the first knuckle including a fixed portion (80) mounted to the turntable adjacent to an outer periphery of the turntable, a locking flange (88) extending radially outward of the tilt axis, a rotatable portion (84) cooperating with the fixed portion having a first flange (94) with an arcuate channel (98) spaced radially outward of the tilt axis and a second flange (96) having a scale provided thereon, and a locking member (92) extending through the arcuate channel in the first flange and into a passage in the locking flange of the fixed portion. The second flange is on an opposite side of the tilt axis to the first flange, the scale on the second flange cooperates with an indicator on the fixed portion, and the first and second opposing flanges lie in a plane generally perpendicular to the tilt axis.

Description

NEW ZEALAND 52 0 6 4. 8 PATENTS ACT 1953 COMPLETE SPECIFICATION After United States Patent Application No. 60/311469 filed on 10 August 2001 Davies Collison Cave Reference: 2560470 APPLICANT(S) TechTronic Industries Co., Ltd. a Hong Kong Company of 24/F, CDW Building 388 Castle Peak Road, Tsuen Wan, New Territories, Hong Kong ADDRESS FOR SERVICE: DAVIES COLLISON CAVE Patent & Trade Mark Attorneys c/- James & Wells Level 9, Ellerslie Tower 60 Cawley Street, Ellerslie, Auckland New Zealand INVENTION TITLE: Bevel adjustment mechanism for a compound miter saw We/I, TechTronic Industries Co., Ltd. hereby declare the invention for which we pray that a patent be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement: INTELLECTUAL PROPERTY OFFICE OF N.Z. 0 9 AUG 2002 RECEIVED P \REC\JMF\0772pnz.doc - 7/8/02 520648 BEVEL ADJUSTMENT MECHANISM FOR A COMPOUND MITER SAW The present invention relates to a compound miter saw and in particular to a bevel adjustment mechanism for a compound miter saw.

Miter saws are used to cut wood and other materials at precise angles. For example, compound miter saws are used to cut crown moldings, cove moldings, and other trim pieces and structural members at single or compound angles. Compound miter saws generally have a circular saw blade that is rotated at a high me of speed to cut a workpiece. 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 generally retained oc a supporting table that, in conjunction with a fence, is used to position the workpiece for cutting by the saw blade.

Many prior art compound miter saws include a pivot arrangement allowing the adjustment of a saw blade through both a horizontal and a vertical plane. A typical pivot arrangement includes a first knuckle which pivotally connects an arm having a saw blade and a motor driving the saw blade mounted to the arm to a turntable. The first knuckle permits the saw blade to move towards and away from the turntable through a vertical plane. A second knuckle allows the the saw blade to be inclined at an angle relative to the top surface of the turntable to make a miter cut in die workpiece. Although compound miter saws are very effective in making miter and compound miter joints, the joint cuts are often imprecise and not sufficiently repeatable for detailed works, such as for fine furniture or cabinetry work. Additionally, the position locking of 11 JUN 2003 1 P:VOPER\JPN\520648 nz cpe.doc-04/06/03 5206A8 many current compound miter saw pivot arrangements do not sufficiently lock the saw assembly in a cutting position, which can lead to imprecise cuts or even possible injury to the operator.

Accordingly, preferred embodiments of the present invention seek to provide a compound miter saw having a bevel adjustment mechanism which improves the cutting accuracy of the saw blade. Preferred embodiments of the invention seek to provide a compound miter saw having a bevel adjustment mechanism which locks the saw assembly in position during the cutting operation. Preferred embodiments of the invention seek to 10 provide a compound miter saw having a bevel adjustment mechanism which includes a direction indicator to assist the operator in determining the angular position of the saw blade during the cutting operation.

In accordance with the present invention, there is provided a miter saw including: 15 abase; a turntable rotatably mounted to the base having a planar upper surface; a fence assembly affixed to the base; a saw assembly including an elongate arm having a fixed end pivotally attached to the turntable, a distal end forming a handle and a central region therebetween; 20 a motor assembly disposed on the elongate arm, the motor assembly including a rotary spindle supporting a cutting disk and a motor operatively connected to the rotary spindle; and a bevel adjustment mechanism for adjusting the angle of inclination of the cutting disk relative to the turntable upper surface, the bevel adjustment mechanism including a 25 first knuckle for adjusting the angle of inclination of the cutting disk about a tilt axis, the first knuckle including a fixed portion mounted to the turntable adjacent to an outer periphery of the turntable, a locking flange extending radially outward of the tilt axis, and a rotatable portion cooperating with the fixed portion having a first flange with an arcuate channel spaced radially outward of the tilt axis and a second flange having a scale provided 30 thereon, the second flange being on an opposite side of the tilt axis to the first flange, the scale on the second flange cooperating with an indicator on the fixed porti^IHSocking J 1 JUN 2003 P:\0PER\JPN\S20648 nz spc.doc-04/06/03 52 0 6 A 8 member extending through the arcuate channel in the first flange and into a passage in the locking flange of the fixed portion, wherein the first and second opposing flanges lie in a plane generally perpendicular to the tilt axis.

In one embodiment, a compound miter saw of the present invention includes a base, a turntable rotatably mounted to the base having a planar upper surface and a fence assembly affixed to the base. A saw assembly is pivotally mounted to the turntable. The saw assembly includes an elongate arm having a fixed end pivotally attached to the turntable, a distal end forming a handle and a central region therebetween. A motor 10 assembly is disposed on the elongate arm and includes a rotary spindle, a cutting disk mounted on the rotary spindle. A motor is disposed within the housing and is operatively connected to the rotary spindle.

A bevel adjustment mechanism is provided for adjusting the angle of inclination of 15 a cutting disk relative to a top surface of a turntable. The bevel adjustment mechanism includes a first knuckle for adjusting the angle of inclination of the cutting disk about a tilt axis and a second knuckle for adjusting the upward and downward movement of the cutting disk. The first knuckle includes a fixed portion mounted to the turntable adjacent with the outer periphery having a locking flange extending radially outward of the tilt axis. 20 A rotatable portion having a first flange with an arcuate channel spaced radially outward of the tilt axis and an opposing second flange having a scale provided thereon cooperates with the fixed portion. A locking member extends through the arcuate channel in the flange of the rotatable portion into a passage in the locking flange of the fixed portion to secure a saw assembly in position.

A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: FIGURE 1 is a perspective view of a compound miter saw in accordance with the 30 present invention; IPONZ 11 JUN 2003 P:VOPER\JPN\S2064S nz spe.doc-02/06/03 520 6 A 8 FIGURE 2 is a perspective view of the compound miter saw shown in FIGURE 1, in the cutting position; FIGURE 3 is a rear plan view of the compound miter saw shown in FIGURES 1 and 2; FIGURE 4 is a side perspective view of the bevel adjustment mechanism of the compound miter saw shown in FIGURES 1 to 3; FIGURE 5 is a perspective view of the bevel adjustment mechanism of the compound miter saw shown in FIGURES 1 to 4; and FIGURE 6 is a rear plan view of the bevel adjustment mechanism of the compound miter saw shown in FIGURES 1 to 5.

IPONZ 11 JUN 2003 52 0 6 4 8 Referring to Figures 1 and 2, a compound miter saw 10 according to a preferred embodiment of the present invention comprises a support member or base 12 having a circular turntable 14 rotatably mounted thereon. Base 12 and turntable 14 collectively deiine on their upper surface a generally planar work support surface. A miter lock handle 16 extends radially from one end of the turntable 14 to lock the turntable to the base 12 at a desired position. A scale 18 is provided on an outer edge 20 of the base 12 to measure die rotational position of die turntable about a generally vertical axis 22. Turotable 14 is rotated relative to the base 12 about axis 22 by releasing and relocking miter lock handle 16 which permits an operator to rotate turntable 14 relative to die base 12 to a desired position about axis 22. An indicator 24 on miter lock handle 16 extends towards scale 18 to provide the rotational position of the turntable 14 relative to die base 12.

A fence assembly 26 secured to die base 12 extends across a top surface 28 of turntable 14 to provide a vertical support surface against which a workpiece is located when the workpiece is cut on die miter saw 10. A saw blade slot 30 is formed through the top surface 28 of turntable 14 adjacent fence assembly 26 to receive a saw Made 32 during the cutting operation. Workpiece support extensions 34 are removably mounted to the each side of the base through holes 36 to provide additional support to a workpiece during the cutting operation. A clamp 38 may be mounted on the base 12 opposite fence assembly 26 to secure the workpiece in position during the cutting operation.

A bevel adjustment mechanism 40 secured to the top surface 28 of turntable 14 extends outward beyond die rear periphery 42 of die base 12. Bevel adjustment mechanism 40 includes a first knuckle 44 for pivotally adjusting a saw assembly 46 about a tilt axis 48 and a second knuckle SO for pivotally adjusting the arm assembly about a pivot axis 52 to cause die saw blade 32 to plunge into the workpiece to be cut. A description of the operation of the bevel adjustment mechanism 40 of compound miter saw 10 will be discussed in greater detail below.

IPONZ J > JUN 2003 0 B 4 B Referring additionally now to Figure 3, saw assembly 46 includes an elongate arm 54 having a fixed end 56 pivotally attached to the second knuckle 50 of bevel adjustment mechanism 40 and an opposing distal end 58 terminating at a handle 60. A rotary cutting disk 62 is connected to arm 54 by a rotary spindle (not shown). Rotary cutting disk 62 is typically a circular saw blade or alternatively, an abrasive wheel, releasably secured to the rotary spindle. In the embodiment shown, the rotary cutting disk 62 includes the circular saw blade 32. An electric motor disposed in motor housing 64 is operatively connected to rotary cutting disk 62 through a rotary spindle and drives the rotary spindle via a conventional gear reduction mechanism. A motor cap 65 is provided on an end of the motor housing 64 opposite the saw blade 32. A shaft lock 66 is provided on the motor housing 64 to lock the rotary spindle during a saw blade change.

An upper blade guard 68 is rigidly attached to the arm 54 to enclose the upper half ofAe cutting disk 62. A dust cotfcction port 69 is integrally formed in die upper blade guard 68 adjacent the fixed end 56 of arm 54 to discharge material removed from the workpicce during the cutting operation. A lower Made guard 70 is pivotally mounted to the upper blade guard 68 by a pivot arm 72 wtfwrimg from the second knuckle 50. The lower Made guard 70 is retracted as saw assembly 46 is pivoted downward toward turntable 14, allowing the saw blade 32 to contact the workpiece for the cutting operation.

Handle 60 of saw assembly 46 is provided at the distal end 58 of arm 54. In a preferred embodiment of the invention shown in the Figures, handle 60 comprises a "D" shaped handle integrally formed with and extending from the motor housing 64. Handle 60 includes a trigger 74 oriented to be proximate the operator's index finger and a palm grip portion 76. To perform die cutting operation, the operator grasps handle 60 and turns on die saw by depressing trigger 74 to cause the motor to rotate the cutting disk 62 on the rotary spindle. It should be understood that a variety of handle arrangements may be incorporated with the compound miter saw 10 of the present invention, such as a conventional "pistol grip" handle arrangement provided at the distal end 58 of arm 54.

IPON2 J I JUN 2UQ3 52 0 6 A Compound miter saw 10 is shown in the lowered or cutting position in Figure 2. Saw assembly 46 is biased from the lowered or cutting position to a raised position by a torsional spring disposed in second knuckle 50 such that, when not in use, the rotary cutting disk 62 is spaced above the upper surface of turntable 14. A pin 77 is biased from an unlocked position to a locked position extending through the second knuckle 50 to lock the saw assembly 46 in the cutting position for transportation. A carry handle 78 is provided on the upper surface of arm 54 to allow an operator to transport the compound miter saw 10 between locations.

Referring now to Figures 4-6, a description of the bevel adjustment mechanism 40 of the compound miter saw 10 of the preferred embodiment is discussed in greater detail. Bevel adjustment mechanism 40 includes a first knuckle 44 permitting the saw assembly 46 to pivot about a tilt axis 48 to make bevel ctrts and compound miter cuts in the workpiece and a second buckle 50 permitting the saw assembly to rotate about pivot axis 52 to move the saw assembly 46 between an 15 inoperative position and a cutting position. The first knuckle 44 comprises a fixed portion 80 secured to the top surface 28 of turntable 14 by bolts 82, a rotating portion 84 for pivotally adjusting a saw assembly 46 about die tilt axis 48 and a boh extending through both the fixed portion 80 and rotating portion 84. The tilt axis 48 of miter saw 10 extends through the bolt provided in the center of first knuckle 20 44.

The fixed portion 80 of first knuckle 44 is cantilevered from the base 12 adjacent an outer edge 20. Fixed portion 80 includes an integrally formed locking flange 88 spaced radially outward of die tilt axis 48. T string flange 88 comprises a passage 90 adapted to receive a locking member 92. Rotating portion 25 84 includes a radially remote spaced first flange 94 and an opposing second flange 96. Remotely spiced first flange 94 includes an arcuate channel 98 corresponding to passage 90 m locking flange 88 which receives locking member 92. The first knuckle includes an annular rib formed on an inner periphery of fixed portion 80, an opposing groove cooperating with the annular rib formed on the inner periphery 30 of the rotating portion 84, and a pocket defined therebetween. A torsional spring is disposed within the pocket of the first knuckle 44 and cooperates with the annular _6_ IPONZ A 1 Jim 520 6 ^ 8 Utm J Vi.;- rib and groove to control the rotation of the rotating portion 84 relative to the fixed portion 80.

Locking member 92 extends through the arcuate dame! 98 in flange 94 into a threaded passage 90 in locking flange 88 to secure the rotating portion 84 to die fixed portion 80. Locking member 92 includes a knob 100 provided at a first end and a post extending from die knob terminating at a threaded portion at an opposing end. In the embodiment of the invention shown, locking member 92 is disposed on die rear side of die miter saw 10 and secures rotating portion 84 to fixed portion 80 at a position along the tilt axis 48. In an alternative embodiment of the invention, a locking flange is provided on the rotating portion of the first knuckle. A locking mechanism having a handle and a rod extending below the top surface of the base is provided on die front side of the saw. The rod extends below the base and through an arcuate channel formed ma radially remotely spaced flange of die fixed portion of die first knuckle to adjustably position die rotating portion relative to die fixed portion.

Second flange 96 is provided on rotating portion 84 of first knuckle 44 opposite die locking flange 88 of fixed portion 80 and first flange 94 of rotating portion 84. A scale 102 is mounted on a front face of the second flange 96. An indicator 104 is disposed on the fixed portion 80 of first knuckle 44 and cooperates with scale 102 to measure the angle of inclination of the saw blade 32 as the saw assembly 46 pivots about the tilt axis 48. The first and second flanges 94, 96 are generally in a plane perpendicular to tilt axis 48.

In operation, the saw assembly 46 is rotated about tilt axis 48 by disengaging the threaded post of locking member 92 from the passage 90 of the locking flange 88. When disengaged, rotating portion 84 of first knuckle 44 is free to rotate about the tilt axis 48 to alter the angle of inclination of the saw blade relative to the top surface 28 of the turntable 14. The arcuate channel 98 of first flange 94 engages locking member 92 at either end of the channel, restricting the rotation of the saw assembly 46 about tilt axis 48.

IPONZ It JUN2003 ? 0 6 4 8 As the rotating portion 84 is pivoted about tilt axis 48, the scale 102 on the second flange 96 rotates relative to the indicator 104 on fixed portion 80 to measure the angle of inclination of the saw blade 32. Once the operator has positioned die saw assemb'y at the desired angle of inclination, the operator rotates the locking member 92. The threaded portion of the post of locking member 92 engages the threaded passage 90 of the locking flange 88 to draw the knob 100 of locking member 92 against the flange 94. Once tightened, locking member 92 forces flange 94 against locking flange 88 to secure die saw assembly in position.

A second knuckle SO of bevel adjustment mechanism 40 allows the saw assembly to pivot between an inoperative position and a cutting position about pivot axis 52. The inner perqvheiy of the second knuckle 50 comprises an annular rib, a groove cooperating with die annular rib formed on the opposing side of the inner periphery and a pocket defined therebetween. A torsional spring is disposed within the pocket of the second knuckle 50 and cooperates with die annular rib and groove to control the rotation of the second knuckle 50 about pivot axis 52.

A bolt 106 wrtMnh through the center of the second knuckle 50 and the fixed end 56 of elongate arm 54 of the saw assembly 46 to secure the saw assembly 46 to die bevel adjustment mechanism 40. The pivot axis 52 of saw 10 extends generally horizontally through bolt 106 in the center erf die second knuckle 50 and is normal relative to the plane of the saw blade 32. The saw assembly 46 is pivotable towards and away from the top surface 28 of turntable 14 between a rest position and a cutting position. The saw assembly 46 is resiliency biased toward the inoperative position above the turntable 14 by the torsional spring in die second knuckle 50, requiring the operator to displace die saw assembly 46 against the force of the bias of the torsional spring to move die saw assembly 46 into the cutting position.

A projection 108 provided on the fruit surface of die second knuckle 50 cooperates with limit stops 110,112 on the fixed portion 80 of first knuckle 44 to restrict the travel of the saw assembly 46 about the tilt axis 48. Projection 108 is generally "V" shaped and includes a first stop portion 114 and a second stop IPONZ 11 JUN 2003 ?OR48 portion 116. In die upright position shown in die Figures, a first limit stop 110 engages die bottom surface of die first stop portion 114 of projection 108. When the saw assembly is routed about die tilt axis 48, second limit stop 112 restricts the over rotation of the saw assembly 46 by engaging the bottom surface of second stop 5 portion 116. The height of first and second limit stops 110,112 are adjustable to allow the operator to increase or decrease the limit angle of inclination for the saw assembly 46.

The preferred embodiment has been described by way of example only and modifications are possible within the scope of the invention.

IPONZ 11 JUN 2003

Claims (4)

« I P;V0PER\JPN\520648 nz spe.doc-04/06/03 - A / • -10- THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A miter saw including: abase; 5 a turntable rotatably mounted to the base having a planar upper surface; a fence assembly affixed to the base; a saw assembly including an elongate arm having a fixed end pivotally attached to the turntable, a distal end forming a handle and a central region therebetween; a motor assembly disposed on the elongate arm, the motor assembly including a 10 rotary spindle supporting a cutting disk and a motor operatively connected to the rotary spindle; and a bevel adjustment mechanism for adjusting the angle of inclination of the cutting disk relative to the turntable upper surface, the bevel adjustment mechanism including a first knuckle for adjusting the angle of inclination of the cutting disk about a tilt axis, the 15 first knuckle including a fixed portion mounted to the turntable adjacent to an outer periphery of the turntable, a locking flange extending radially outward of the tilt axis, and a rotatable portion cooperating with the fixed portion having a first flange with an arcuate channel spaced radially outward of the tilt axis and a second flange having a scale provided thereon, the second flange being on an opposite side of the tilt axis to the first flange, the 20 scale on the second flange cooperating with an indicator on the fixed portion, and a locking member extending through the arcuate channel in the first flange and into a passage in the locking flange of the fixed portion, wherein the first and second opposing flanges lie in a plane generally perpendicular to the tilt axis. 25

2. A miter saw as claimed in claim 1, wherein the bevel adjustment mechanism further includes a second knuckle for allowing the saw assembly to pivot between an inoperative position and a cutting position about an axis substantially perpendicular to the tilt axis, and the second knuckle is provided with a spring for resiliently biasing the saw assembly to the inoperative position. 30

3. A miter saw as claimed in claim 2, wherein the spring is a torsional spring in the IPONZ 11 JUN 2003 P:V0PER\JPN\520648 nz spc.doc-06/06/03 52066 0 second knuckle.

4. A miter saw substantially as hereinbefore described with reference to the drawings and/or Examples. DATED this 6th day of June, 2003 END OF CLAIMS TechTronic Industries Co., Ltd. By DA VIES COLLISON CAVE Patent Attorneys for the Applicant IPONZ 11 JUN 2003