CN220144897U

CN220144897U - Power tool and dicing saw

Info

Publication number: CN220144897U
Application number: CN202321508038.0U
Authority: CN
Inventors: H·F·范登布什; J·E·施米茨; K·M·卡梅伦; D·R·拉姆勒; G·M·森伯; A·J·帕斯科夫
Original assignee: Milwaukee Electric Tool Corp
Current assignee: Milwaukee Electric Tool Corp
Priority date: 2022-06-13
Filing date: 2023-06-13
Publication date: 2023-12-08
Anticipated expiration: 2033-06-13

Abstract

A power tool, comprising: a housing; a trigger; a motor supported within the housing; a saw blade interconnected with the housing by a support arm and drivably coupled to the motor; a main handle integrally formed with the housing; an auxiliary handle coupled to the housing and disposed between the saw blade and the main handle; and a battery receptacle defined by the housing and positioned below the main handle. The battery receptacle is configured to receive a battery pack to supply current to the motor. The power tool further includes a splash guard integrally formed with the housing and positioned between the battery receptacle and the saw blade.

Description

Power tool and dicing saw

Cross Reference to Related Applications

The present utility model claims priority from U.S. provisional patent application No. 63/408,552 filed on month 21 of 2022 and U.S. provisional patent application No. 63/351,487 filed on month 13 of 2022, the disclosures of which are incorporated herein by reference in their entireties.

Technical Field

The present utility model relates to dicing saws and more particularly to battery powered dicing saws.

Background

Power tools, such as dicing saws, generally have many applications. The dicing saw may be held directly by a user for operation or may be supported by a cart. During operation, the dicing saw can make precise cuts in a ground surface (such as concrete or asphalt). The cutting saw can also cut steel bars, metal pipes, PVC pipes and wall surfaces.

Disclosure of Invention

In one aspect, the present utility model provides a power tool comprising: a housing; a trigger; a motor supported within the housing; a saw blade interconnected with the housing by a support arm and drivably coupled to the motor; a main handle integrally formed with the housing; an auxiliary handle coupled to the housing and disposed between the saw blade and the main handle; and a battery receptacle defined by the housing and positioned below the main handle. The battery receptacle is configured to receive a battery pack to supply current to the motor. The power tool further includes a splash guard integrally formed with the housing and positioned between the battery receptacle and the saw blade.

In another aspect, the present utility model provides a power tool comprising: a housing; a motor supported within the housing; a saw blade interconnected with the housing by a support arm and drivably coupled to the motor; and a main handle coupled to the housing. The main handle has a front end proximate the saw blade and an opposite rear end. The power tool further includes: an auxiliary handle disposed between the saw blade and the main handle; and a harness removably coupled to the main handle at a first attachment point at a rear end of the main handle and at a second attachment point on the support arm.

In another aspect, the present utility model provides a power tool configured to be supported by a cart including a frame, a mounting assembly securing the power tool to the frame, and a remote actuation system having a first electrical connector, a cart control unit, and a wire configured to interconnect the first electrical connector with the cart control unit. The remote actuation system is operable to activate and deactivate the power tool when the power tool is secured to the frame. The power tool includes: a housing; a motor supported within the housing; a saw blade drivably coupled to the motor; a trigger; a saw control unit supported within the housing and configured to activate and deactivate the motor in response to a first input control signal from the trigger; and a second electrical connector in communication with the saw control unit and configured to be electrically connected to the first electrical connector of the cart. A second input control signal is transmitted from the cart control unit to the saw control unit via the first and second electrical connectors by wires to selectively activate the motor and the saw blade and change the rotational speed of the motor and the saw blade.

In another aspect, the present utility model provides a power tool comprising: a housing; a trigger; a motor supported within the housing; a saw blade interconnected with the housing by a support arm and drivably coupled to the motor; a battery receptacle configured to receive a battery pack to supply current to the motor; and a controller connected to the trigger, the motor, and the battery receptacle. The controller is configured to: driving a motor in response to actuation of a trigger; releasing the drive of the motor to allow the motor to coast for a first predetermined period of time in response to the release of the trigger; and braking the motor in response to the first predetermined period of time being met.

In another aspect, the present utility model provides a dicing saw comprising: a housing; a motor supported within the housing; a saw blade interconnected with the housing by a support arm and drivably coupled to the motor; and a main handle coupled to the housing. The main handle has a trigger and has a front end adjacent the saw blade opposite the rear end. The dicing saw further comprises: an auxiliary handle disposed between the saw blade and the main handle; and an electronic control unit supported within the housing. The electronic control unit is configured to enable and disable the motor in response to an input control signal from the trigger. The electronic control unit includes a heat sink having a plurality of fins defining channels between adjacent fins such that a first airflow path flows through the channels during operation of the motor. Each of these fins has a corrugated surface.

Drawings

Fig. 1 is a side perspective view of a dicing saw according to an embodiment of the utility model.

Fig. 2 is an opposite side perspective view of the dicing saw of fig. 1.

Fig. 3 is a rear perspective view of the dicing saw of fig. 1.

Fig. 4 is a bottom perspective view of the dicing saw of fig. 1.

Fig. 5 is a cross-sectional view of the dicing saw of fig. 1 with portions removed.

Fig. 6A is an opposite cross-sectional view of the dicing saw of fig. 5 with portions removed.

Fig. 6B is a perspective view of the potting boat assembly (potting boat assembly) in the dicing saw of fig. 6A.

Fig. 6C is a top perspective view of the heat sink of the potting boat assembly of fig. 6B.

Fig. 6D is a bottom perspective view of the heat sink of fig. 6C.

Fig. 6E is an end view of a portion of the heat sink of fig. 6C.

Fig. 7A is a perspective view of the dicing saw of fig. 1, showing the interior of the support arm.

Fig. 7B is an enlarged view of the dicing saw of fig. 7A, showing the belt tensioning assembly.

Fig. 8 is a cross-sectional view of the dicing saw of fig. 1 taken along line 8-8 in fig. 2, revealing the interior of the support arm.

Fig. 9 is an enlarged view of the dicing saw of fig. 1, showing the rear handle of the saw.

Fig. 10 is an enlarged view of the dicing saw of fig. 1, showing a portion of the support arm.

Fig. 11 is an enlarged view of a support arm of the dicing saw of fig. 1.

Fig. 12 is an enlarged view of the support arm of the dicing saw of fig. 1 with portions removed.

Fig. 13 is an enlarged view of the dicing saw of fig. 1, showing a portion of the fluid dispensing system.

Fig. 14 is a side view of the cutting saw of fig. 1 with the saw blade removed.

Fig. 15 is a side view of the dicing saw of fig. 1.

Fig. 16 is a side view of the dicing saw of fig. 14 with a battery pack attached.

Fig. 17 is a side view of the dicing saw of fig. 1 with a battery pack attached.

Fig. 18 is a block diagram of a controller for the dicing saw of fig. 1 according to embodiments described herein.

Fig. 19 is a circuit diagram of a switching network according to embodiments described herein.

FIG. 20 is a block diagram of a method performed by the controller of FIG. 18, according to embodiments described herein.

FIG. 21 is a block diagram of another method performed by the controller of FIG. 18, according to embodiments described herein.

FIG. 22 is a block diagram of another method performed by the controller of FIG. 18, according to embodiments described herein.

Fig. 23A is a block diagram of another method performed by the controller of fig. 18, according to embodiments described herein.

Fig. 23B is a block diagram of another method performed by the controller of fig. 18, according to embodiments described herein.

FIG. 24 is a block diagram of another method performed by the controller of FIG. 18, according to embodiments described herein.

Fig. 25 is a block diagram of another method performed by the controller of fig. 18 according to embodiments described herein.

Fig. 26 is a diagram of an indicator indicating various motor current levels according to embodiments described herein.

FIG. 27 is a diagram of an indicator indicating various system performance levels according to embodiments described herein.

Before any embodiments of the utility model are explained in detail, it is to be understood that the utility model 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 utility model 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.

Detailed Description

Fig. 1-4 illustrate a hand-held power tool 10, which in the illustrated embodiment is a dicing saw. The saw 10 includes a housing 15, a support arm 20 coupled to and extending from the housing 15, a cutting wheel 25 carried by the support arm 20, and a guard 30 covering a portion of the circumference of the cutting wheel 25. The cutting wheel 25 may be a blade, an abrasive disk, or any other rotatable element capable of removing material from a workpiece. In the illustrated embodiment, the cutting wheel 25 has a diameter greater than 9 inches and preferably has a diameter of 14 inches. In other embodiments, the diameter of the cutting wheel 25 may be between about 10 inches and about 16 inches.

The housing 15 shown is a clamshell housing having cooperating left and right halves 35, 40. A first or rear handle 45 extends from a rear portion of the housing 15 in a direction generally opposite the support arm 20. A power button 48 (fig. 9) and trigger 50 for operating the saw 10 are located on the rear handle 45. In the illustrated embodiment, the saw 10 further includes a second or front handle 55 secured to the housing 15 and surrounding an upper portion of the housing 15. The front handle 55 and the rear handle 45 provide a gripping area to facilitate two-handed operation of the saw 10.

Referring to fig. 5, 6A and 6B, the saw 10 further includes a motor housing 60 formed in the housing 15 at a front lower portion of the housing 15. An electric motor 62 is positioned in the motor housing 60. The motor 62 is preferably a brushless direct current ("BLDC") motor. The operation of the motor 62 is governed by an electronic control unit 65 that includes a printed circuit board ("PCB") housed within the potting boat assembly 70 and at least two independent resistors 67 positioned below the potting boat assembly 70 without being on the PCB. The PCB includes FETs (not shown) mounted to the top of the PCB, which is located within the potting boat assembly 70 and covered with a potting material (e.g., epoxy). The resistors 67 are mounted to respective heat sinks 74 that are spaced apart from one another and connected by brackets 76 that also serve as baffles, as explained in further detail below.

Fig. 6B shows a potting boat assembly 70 without PCB or potting material therein. The potting boat assembly 70 includes a heat sink 71 and a frame 72 attached to the heat sink 71. In some embodiments, the heat sink 71 may be secured to the frame 72 by a plurality of fasteners (not shown) that are received in a first set of mounting holes 73 disposed along an inner edge of the frame 72 and a second set of mounting holes 75 (fig. 6C) formed in a top surface 77 of the heat sink 71. The frame 72 is formed of a plastic material, and the heat sink 71 is formed of a metal alloy such as aluminum 6063. Aluminum 6063 provides heat sink 71 with a thermal conductivity of 218W/m-K that is higher than the thermal conductivity of other aluminum alloys conventionally used for heat sinks (e.g., aluminum a380, which has a thermal conductivity of 109W/m-K). In this manner, the increased thermal conductivity of the heat sink 71 more efficiently cools the heat-generating electronic components on the PCB.

Referring to fig. 6B to 6D, the top surface 77 of the heat sink 71 further includes a stage 81 that is elevated above a surrounding portion of the top surface 77. The platform 81 is configured to support the PCB when the PCB is received within the potting boat assembly 70. The heat sink 71 also includes a plurality of parallel fins 79 extending along the length of the heat sink 71 along opposite bottom surfaces of the heat sink 71. In some embodiments, the heat sink 71 includes 20 rows of fins 79. As shown in fig. 6D, some fins 79 extend along the entire length of the heat sink 71, while other fins 79 include gaps 83 along their length to form a plurality of discrete fins 79 within a single row.

Referring to fig. 6E, each fin 79 includes a first side 85, a second side 87 spaced from the first side 85, and a bottom surface 89 extending between the sides 85, 87. The first side 85 and the second side 87 are wavy rather than flat, defining alternating peaks and valleys. The corrugated fins 79 are provided with an increased surface area compared to fins having flat side surfaces through which heat transfer can occur. Each fin 79 of the illustrated embodiment has 6% more surface area than a fin with a flat side surface. In this manner, the total surface area of the heat sink 71 is 6% greater than a conventional heat sink having fins with flat sides because the corrugated fins 79 only increase the surface area of each fin 79, not the entire heat sink 71.

Referring to fig. 1-4, the saw 10 illustrated is a cordless electric saw and includes a battery or battery pack 78 (fig. 16 and 17) that provides current to the motor 62. The battery pack 78 is removably coupled to a battery receptacle 80, which in the illustrated embodiment is on a lower portion of the housing 15 (fig. 1). As such, when the battery pack 78 is coupled to the receptacle 80, the rear handle 45 is positioned above the battery receptacle 80. In other embodiments, the saw 10 may be a corded electric saw configured to receive power from a wall outlet or other remote power source. In another embodiment, the saw 10 is configured to be supported by a cart (not shown) rather than being hand-held, as described herein below.

The battery pack 78 is a power tool battery pack and includes a battery housing 82 (fig. 16 and 17) and a plurality of rechargeable battery cells (not shown) disposed within the battery housing 82. The battery cells are lithium-based battery cells, but may alternatively have any other suitable chemical composition. The battery pack 78 has a nominal output voltage of about 80V. The battery pack 78 may also have different nominal voltages, such as 36V, 40V, 72V, between 36V and about 80V, or greater than 40V.

With continued reference to fig. 1-4, the housing 15 of the saw 10 includes a splash guard 84 integrally formed along a rear lower portion of the housing 15. The splash guard 84 extends in a direction generally opposite the support arm 20 and partially defines the battery receptacle 80 such that the splash guard 84 prevents debris, dust, and fluids generated when the saw 10 is operated from contacting the battery pack 78 when the battery pack is attached to the receptacle 80.

The saw 10 further includes a pair of wheels 86a, 86b adjacent the front portion of the housing 15 that are rotatably supported by respective first 88 and second 90 wheel mounts (fig. 4). One wheel 86a is coupled to the support arm 20 by a first wheel mount 88 integrally formed with the support arm 20. The other wheel 86b is coupled to the left half 35 of the housing 15 by a second wheel mount 90, with the front handle 55 disposed between the second wheel mount 90 and the left half 35 of the housing 15.

Referring to fig. 1, 9 and 10, the saw 10 further includes a strap 92 configured to be removably coupled to the saw 10 and worn along a shoulder of a user to support the weight of the saw 10 during transportation of the saw 10. The strap 92 includes a first end 94 and a second end 96 configured to be removably coupled to the saw 10 at a first attachment point 98 (fig. 9) and a second attachment point 100 (fig. 10), respectively. The first end 94 and the second end 96 of the strap 92 each have a securing member 102 (e.g., clip or latch, fig. 1) configured to latch onto a first attachment point 98 and a second attachment point 100, respectively, of the saw 10. The first attachment point 98 is positioned at the rear end 104 of the rear handle 45 and the second attachment point 100 is positioned along the support arm 20. A recess 106 with a stem 108 is provided at both the first attachment point 98 and the second attachment point 100 such that the securing member 102 at the first end 94 and the second end 96 of the strap 92 may be attached to the saw 10. The back strap 92 further includes a shoulder pad 110 (fig. 1) that is slidable between the first end 94 and the second end 96 of the back strap 92. The shoulder pad 110 of the back strap 92 allows the user to comfortably wear the back strap 92 while transporting the saw 10.

Referring to fig. 7A and 8, the saw 10 includes a drive assembly 150 for transmitting torque from the motor 62 to the cutting wheel 25. The driving assembly 150 includes: a drive pulley 154 fixed to an output shaft (not shown) of the motor 62; a driven pulley 158 connected to the drive pulley 154 by a belt 162; a main shaft 166 fixed to the driven pulley 158; and a clamp assembly 170 coupled to the spindle 166. In some embodiments, a clutch mechanism may be provided between the output shaft and the drive pulley 154 to selectively interrupt torque transfer between the output shaft and the drive pulley 154. The clamp assembly 170 includes flanges 174a, 174b (fig. 8) that apply a clamping force to the cutting wheel 25.

Saw 10 further includes a belt tensioning assembly 178 (fig. 7A and 7B) configured to apply tension to belt 162 to maintain an appropriate amount of belt wrap on each of pulleys 154, 158 and to maintain tension in belt 162. As shown in fig. 7B, the belt-tensioning assembly 178 includes a tensioning arm 180 having a first end 184, a second end 188 opposite the first end 184, a recess 192 between the first end 184 and the second end 188, a tensioning pulley 196, and a spring 200. A fastener 204 secured to the support arm 20 is received through the recess 192 of the tensioning arm 180. The tensioning arm 180 is pivotally coupled to the support arm 20 by a pin 220 positioned along the first end 184 of the tensioning arm 180. A tensioning pulley 196 is coupled to the second end 188 of the tensioning arm 180. To tension belt 162, spring 200 is configured to apply a clockwise moment to tensioning arm 180 to pivot tensioning arm 180. As tensioning arm 180 pivots, tensioning pulley 196 engages belt 162 to tension belt 162. The pivotal movement of the tensioning arm 180 is limited by a fastener 204 received within a recess 192 of the tensioning arm 180.

The drive pulley 154 defines a first axis of rotation 182 and the driven pulley 158 defines a second axis of rotation 186 spaced apart from the first axis of rotation 182. The support arm 20 includes: a first arm portion 190 (fig. 1) coupled to the housing 15; and a second arm portion 194 or cover (fig. 1) coupled to the first arm portion 190 and configured to enclose the drive assembly 150 during normal operation. The second arm portion 194 is coupled to the first arm portion 190 by a screw, but may be attached by a snap fit or any other suitable means in other embodiments. The interior of the first arm portion 190 defines a wall 198 that encloses the drive pulley 154 and the driven pulley 158 of the drive assembly 150. The wall 198 of the first arm portion 190 is configured to prevent debris and dust from contacting the drive assembly 150. In the illustrated embodiment, the motor housing 60 is secured to the first arm portion 190 by a plurality of bolts 152 (fig. 6 and 7A). The output shaft of the motor 62 extends through the first arm portion 190 to the drive pulley 154. The spindle 166 also extends through the first arm portion 190 and is supported by two bearings 206, 208 (fig. 8).

The battery receptacle 80 is defined by a first wall 210 (fig. 1) parallel to a top surface 212 of the housing 15 and a second wall 214 (fig. 5) oriented at an oblique angle A1 relative to the first wall 210. The first wall 210 and the second wall 214 of the battery receptacle 80 are oriented at oblique angles A2, A3 relative to the longitudinal axis 216 of the support arm 20 (fig. 7A). The longitudinal axis 216 of the support arm 20 extends in a direction transverse to the first rotational axis 182 of the drive pulley 154 and the second rotational axis 186 of the driven pulley 158. In some embodiments of the saw 10, the first wall 210 is oriented at an angle A2 of about 140 degrees relative to the longitudinal axis 216 of the support arm 20 and the second wall 214 is oriented at an angle A3 of about 80 degrees relative to the longitudinal axis 216 of the support arm 20. The first wall 210 of the battery receptacle 80 is also oriented at an angle A4 (fig. 7A) of about 34 degrees relative to a handle axis 217 defined by the rear handle 45 of the saw 10.

The belt 162 shown is a timing belt having a plurality of teeth 218 (fig. 7B) extending laterally across the width of the belt 162. The teeth 218 may engage corresponding teeth on the driven sheave 158 and the drive sheave 154. The toothed engagement between the timing belt 162 and the pulleys 154, 158 prevents the belt 162 from slipping under high loads, which may occur with V-belts. Furthermore, the relatively flat profile of the timing belt 162 allows the diameter of the drive pulley 154 to be smaller as compared to a V-belt configuration. In this manner, a higher reduction in speed between the drive pulley 154 and the driven pulley 158 may be achieved. For example, in some embodiments, the drive pulley 154 and the driven pulley 158 may be sized to provide a 4:1 reduction from the motor output shaft to the main shaft 166. In other embodiments, the drive pulley 154 and the driven pulley 158 may be sized to provide a reduction between 3:1 and 5:1 from the motor output shaft to the main shaft 166.

Referring to fig. 11 and 12, the support arm 20 may include a rubber stopper 224 removably coupled to the second arm portion 194 of the support arm 20. The rubber stopper 224 is configured to be inserted into an access hole 228 extending through the second arm portion 194. Rubber stopper 224, when placed into access hole 228, prevents debris from entering the interior of support arm 20 and from blocking drive assembly 150.

Fig. 14-17 illustrate the saw 10 with an origin O at the center of the cutting wheel 25, the origin O defining a coordinate system including an X-axis extending along the longitudinal axis of the saw 10, a Y-axis extending perpendicular to the longitudinal axis of the saw 10, and a Z-axis (not shown) extending transverse to the longitudinal axis of the saw 10. In various embodiments of the saw 10, the center of gravity CG of the saw 10 is located in a negative direction (i.e., rearward or leftward) of the origin O.

Referring to fig. 14, saw 10 weighs 19.76 pounds without battery pack 78 and cutting wheel 25 attached. As a result, the center of gravity CG of the saw 10 is positioned-212 mm to-214 mm along the X-axis, 4mm to-6 mm along the Y-axis, and 3mm to-5 mm along the Z-axis from the origin O. Referring to fig. 15, with the cutting wheel 25 attached, the saw 10 weighs in the range of 22.50 pounds to 23.10 pounds. The center of gravity CG of the saw 10 is then positioned from the origin O along the X-axis-181 mm to-183 mm, along the Y-axis-3.25 mm to-5.25 mm, and along the Z-axis-2.25 mm to-4.25 mm. Referring to fig. 16, with the battery pack 78 attached but the cutting wheel 25 removed, the saw 10 weighs in the range of 29.10 pounds to 29.7 pounds and the center of gravity CG is positioned from the origin O along the X-321 mm to-323 mm, along the Y-5.5 mm to-7.5 mm, and along the Z-8 mm to-10 mm. Referring to fig. 17, with both the cutting wheel 25 and the battery pack 78 attached, the saw 10 weighs in the range of 32.40 pounds to 33 pounds, and the center of gravity CG of the saw 10 is positioned from the origin O along the X-axis-288 mm to-290 mm, along the Y-axis-4.75 mm to-6.75 mm, and along the Z-axis-7 mm to-9 mm.

Referring to fig. 5 and 6A, the saw 10 further includes an airflow path 232 extending through the housing 15 of the saw 10. The airflow path 232 extends from the air inlet 236 to the air outlet 240 (fig. 4), wherein the air inlet 236 and the air outlet 240 are illustrated as slot-shaped openings that are specifically positioned to protect the interior of the housing 15 from fluids, dust, and debris present during operation of the saw 10. The air inlet 236 is positioned along a rear portion of the housing 15 below the rear handle 45 (fig. 1), while the air outlet 240 is positioned forward of a bottom portion of the saw 10 (fig. 4) and the splash guard 84.

Air is drawn into the housing 15 through the air inlet 236 and immediately splits into a first air flow path 232a and a second air flow path 232b to cool the heat sink 74 associated with the individual resistors 67 and the heat sink 71 of the potting boat assembly 70, respectively. While traveling along the first airflow path 232a, air is forced to flow through the spaces defined between the resistor heat sinks 74. For the second air flow path 232b, air is forced to flow through parallel channels 91 defined by adjacent fins 79 on the bottom surface of the heat sink 71 (fig. 6E). After passing through the resistor radiator 74 and the radiator 71 of the potting boat assembly 70, the first and second airflow paths 232a, 232b again merge into a single airflow path 232 to flow through the motor 62 and then exit through the exhaust port 240. To direct the airflow along the airflow path 232 during operation of the saw 10, a fan (not shown) is provided with the motor 62.

Referring to fig. 1, 2 and 13, the saw 10 further includes a fluid distribution system 300. The fluid distribution system 300 includes: a first connector portion 304; a second connector portion 308 coupled to an upper portion of the housing 15; a control valve 312 coupled to front handle 55 and disposed between first connector portion 304 and second connector portion 308; and a dispenser 316 coupled to the guard 30. A first supply line (not shown) may be attached to the first connector portion 304 to provide fluid, such as water, from an external source (not shown) to the fluid distribution system 300. A second supply line 320 extends from the second connector portion 308 to the dispenser 316. In the illustrated embodiment, the dispenser 316 includes a pair of nozzles 324 disposed on opposite sides of the guard 30 and connected by a third supply line 328. Nozzles 324 are operable to discharge fluid onto each side of cutting wheel 25 for cooling, lubrication, and dust removal. In the illustrated embodiment, an auxiliary handle 330 is attached to the guard 30 adjacent the third supply line 328. However, the third supply line 328 may instead extend through the handle 330.

The control valve 312 of the fluid dispensing system 300 is a manual water valve having a valve handle 314 movable between a first position and a second position. The first position corresponds to a closed state of the valve 312 in which fluid flow from the connector portion 304 to the connector portion 308 is inhibited, and the second position corresponds to an open state of the valve 312 (shown in fig. 13) in which fluid flow from the connector portion 304 to the connector portion 308 is permitted. When the saw 10 is placed on a surface, the valve handle 314 may contact the surface to move from the first position to the second position to adjust the valve 312 to the open condition as shown in fig. 13. In other embodiments of the saw 10, the act of placing the saw 10 on a surface may contact the valve handle 314 with the surface and adjust the valve handle 314 from the second position to the first position to adjust the valve 312 from the open state to the closed state.

In operation of the saw 10, the user presses the power button 48 to turn on the saw 10 for operation. Once ready for operation, the user presses the trigger 50 located on the rear handle 45 to activate the motor 62. The motor 62 outputs torque to the attached drive pulley 154 via an output shaft. The drive pulley 154 is driven in rotation, causing the belt 162, and thus the driven pulley 158 and the spindle 166, to rotate. As the spindle 166 rotates, the cutting wheel 25 rotates to perform a cutting operation. During operation, a user may perform a cutting operation while holding the front and rear handles 55 and 45. The user may also transport the saw 10 over a surface during operation by a pair of wheels 86a, 86 b.

In other embodiments of the saw 10, the fluid dispensing system 300 is electrically connected to the electronic control unit 65. When trigger 50 is depressed to activate motor 62, electronic control unit 65 receives a first electronic signal to allow fluid to flow through fluid distribution system 300. When trigger 50 is released, electronic control unit 65 receives a second electronic signal to stop fluid flow through fluid distribution system 300. In such an embodiment of the saw 10, wherein the fluid dispensing system 300 is electronically controlled by the control unit 65, the control valve 312 may be, for example, a solenoid actuated valve operable between an open state and a closed state in response to actuation by the control unit 65. To control the flow rate of fluid within fluid distribution system 300, a user may adjust control valve 312 to increase or decrease the flow rate of fluid. In this way, the flow rate of fluid exiting nozzle 324 remains constant regardless of the degree to which trigger 50 is depressed.

In another embodiment of the saw 10, the saw 10 is configured to be supported by a cart (not shown) that is capable of transporting the saw 10 over a surface during and between cutting operations. The cart may transport the saw 10 in a forward or rearward direction. The cart includes: a frame to which the saw 10 may be attached; a handle extending upwardly from the frame, which can be grasped by a user to maneuver the cart; a front wheel; and a rear wheel assembly having two rear wheels. The frame comprises: a material discharge guard (e.g., a fender) that prevents material cut by the saw 10 from contacting a user of the cart; and a ring that serves as a lifting point or lifting tab. The mounting assembly of the cart is used to secure the saw 10 to the frame. The mounting assembly includes a front mount on a lower portion of the frame and a rear mount on an upper portion of the frame.

The cart further includes a remote actuation system for activating and deactivating the saw when the saw 10 is supported on the frame. The remote actuation system interfaces with an electrical connector 332 (fig. 3) on the saw 10 to provide input control signals to a saw control unit or electronic control unit 65 on the saw 10 that in turn can activate and deactivate the saw 10. The remote actuation system includes a cart mating electrical connector configured to mechanically and electrically connect to the electrical connector 332 on the saw 10. The remote actuation system further comprises: wires extending from the cart mating electrical connector; the cart control unit, to which the opposite ends of the wires are connected to transmit input control signals from the cart control unit to the saw control unit 65 via the cart mating electrical connectors and electrical connectors 332 to selectively enable and vary the rotational speed of the motor 62 and the cutting wheel 25.

In the illustrated embodiment, the electrical connector 332 is disposed on the rear end 336 (fig. 3) of the saw 10, and the cart control unit is disposed on an upper portion of the handle of the cart. In some embodiments, the cart electrical connector may be located on the lid or housing of the rear mount. In some embodiments, the wires are routed outside of the cart. In other embodiments, the wires are routed entirely inside the cart or partially inside the cart. A rubber stopper (not shown) may be provided and inserted into the connector 332 when the connector is not in use.

The remote actuation system further includes a throttle lever pivotably coupled to the handle of the cart and in communication with the cart control unit to provide input to the cart control unit. In some embodiments, the remote actuation system may further include a locking system including a locking actuator (e.g., a button, not shown) coupled to the handle and in communication with the cart control unit. The locking actuator is movable between a first position and a second position. The cart control unit is operable in an idle mode when the latch actuator is in the first position and in an active mode when the latch actuator is in the second position. When in the active mode, pivoting of the throttle lever causes the cart control unit to output an input control signal to the saw 10 to activate the motor 62, thereby causing the cutting wheel 25 of the saw 10 to rotate. In some embodiments, the rotational speed of the motor 62 varies depending on the degree to which the throttle lever is pivoted, such that when the throttle lever is maximally pivoted, the motor 62 will operate at its maximum rotational speed. When in idle mode, pivoting of the throttle lever does not cause the cart control unit to output an input control signal to the saw 10, and thus pivotal movement of the throttle lever does not activate the motor 62.

A controller 1800 for the saw 10 is shown in fig. 18. The controller 1800 is electrically and/or communicatively connected to the various modules or components of the saw 10. For example, the illustrated controller 1800 is connected to an indicator 1845, a voltage sensor 1870, a speed sensor 1865, a current sensor 1875, an auxiliary sensor 1880, a trigger 50 (via a trigger switch 1858), a power switching network 1855, and a power input unit 1860.

The controller 1800 includes a plurality of electrical and electronic components that provide power, operational control, and protection for the components and modules within the controller 1800 and/or saw 10. For example, the controller 1800 includes, among other things, a processing unit 1805 (e.g., a microprocessor, an electronic processor, an electronic controller, a microcontroller, or another suitable programmable device), a memory 1825, an input unit 1830, and an output unit 1835. The processing unit 1805 includes, among other things, a control unit 1810, an arithmetic logic unit ("ALU") 1815, and a plurality of registers 1820 (shown as a set of registers in fig. 18), and is implemented using a known computer architecture, such as a modified harvard architecture (Harvard architecture), a von neumann architecture (von Neumann architecture), or the like. The processing unit 1805, memory 1825, input unit 1830 and output unit 1835, and the various modules connected to the controller 1800 are connected by one or more control and/or data buses (e.g., a common bus 1840). For illustrative purposes, a control and/or data bus is generally shown in FIG. 18. The interconnection between the various modules and components and the communication between them using one or more control buses and/or data buses will be known to those skilled in the art in view of the embodiments described herein.

Memory 1825 is a non-transitory computer-readable medium and includes, for example, a program storage area and a data storage area. The program storage area and the data storage area may comprise a combination of different types of memory, such as ROM, RAM (e.g., DRAM, SDRAM, etc.), EEPROM, flash memory, hard disk, SD card, or other suitable magnetic, optical, physical, or electronic memory device. The processing unit 1805 is coupled to the memory 1825 and executes software instructions that can be stored in RAM of the memory 1825 (e.g., during execution), ROM of the memory 1825 (e.g., on a generally permanent basis), or another non-transitory computer-readable medium, such as another memory or disk. Software included in an embodiment of the saw 10 may be stored in the memory 1825 of the controller 1800. The software includes, for example, firmware, one or more application programs, program data, filters, rules, one or more program modules, and other executable instructions. The controller 1800 is configured to retrieve from the memory 1825 and execute, among other things, instructions related to the control processes and methods described herein. In other embodiments, the controller 1800 includes additional, fewer, or different components

The controller 1800 drives the motor 1850 in response to user actuation of the trigger 50. Depressing trigger 50 actuates trigger switch 1858, which outputs a signal to controller 1800 to drive motor 1850. In some embodiments, the controller 1800 controls a power switching network 1855 (e.g., FET switching bridge) to drive the motor 1850. For example, the power switching network 1855 may include a plurality of high side switching elements (e.g., FETs) and a plurality of low side switching elements (e.g., FETs). The controller 1800 may control each FET of the plurality of high-side switching elements and the plurality of low-side switching elements to drive each phase of the motor 1850. For example, the power switching network 1855 may be controlled to slow down the motor 1850 faster. Fig. 19 provides an example power switching network 1900, as described in more detail below.

An indicator 1845 is also connected to the controller 1800 and receives control signals from the controller 1800 to turn on and off or otherwise communicate information based on the different states of the saw 10. The indicator 1845 includes, for example, one or more Light Emitting Diodes (LEDs), or a display screen. The indicator 1845 may be configured to display the condition of the saw 10 or information associated with the saw. For example, the indicator 1845 may display information related to the operational status of the saw 10 (such as mode or speed setting). The indicator 1845 may also display information regarding a fault condition or other anomaly (such as excessive motor speed) of the saw 10. In some embodiments, the indicator 1845 displays information related to the amount of power drawn by the motor 1850. In some embodiments, the indicator 1845 indicates whether the controller 1800 is performing a protection operation, such as reducing the duty cycle of the PWM signal used to drive the motor 1850 or turning off the saw 10. In addition to or in lieu of the visual indicator, the indicator 1845 may also include a speaker or a tactile feedback mechanism to convey information to the user through an audible or tactile output.

The battery pack interface 1885 is connected to the controller 1800 and is configured to couple with the battery pack 78. The battery receptacle 80 includes a combination of mechanical components (e.g., a battery pack receiving portion, the battery receptacle 80, etc.) and electrical components configured and operable to interface (e.g., mechanically, electrically, and communicatively connect) the saw 10 with the battery pack 78. The battery pack interface 1885 is coupled to the power input unit 1860. The battery pack interface 1885 transfers power received from the battery pack 78 to the power input unit 1860. The power input unit 1860 includes active and/or passive components (e.g., buck controllers, voltage converters, rectifiers, filters, etc.) to regulate or control the power received through the battery pack interface 1885 that is provided to the controller 1800. In some embodiments, the battery interface 1885 is also coupled to the power switch network 1855. The operation of the power switch network 1855, controlled by the controller 1800, determines how power is supplied to the motor 1850.

The voltage sensor 1870 senses the voltage provided by the battery pack 78, the voltage of the phases of the motor 1850, the total voltage of the phases of the motor 1850, or a combination thereof. The current sensor 1875 senses at least one of a current provided by the battery pack 78, a phase current of the motor 1850, or a combination thereof. The current sensor 1875 may be, for example, an in-line phase current sensor, a pulse width modulated center sampling inverter bus current sensor, or the like. The speed sensor 1865 senses the speed of the motor 1850. The speed sensor 1865 may include, for example, one or more hall effect sensors. Auxiliary sensor(s) 1880 include various other sensors (e.g., accelerometers, workpiece contact sensors, temperature sensors, position sensors, etc.) for monitoring characteristics associated with saw 10.

Fig. 19 illustrates a power switching network 1900. In the illustrated embodiment, the motor 1850 is a brushless DC motor comprising three phases. For example, motor 1850 may include an outer stator having six stator windings arranged in three phases, and an inner rotor having four permanent magnets. However, in other embodiments, different types of motors may be used, such as those having different numbers of phases, windings, and magnets. As shown in fig. 19, power switch network 1900 includes three high-side electronic switches 1912, 1916, 1920 and three low-side electronic switches 1910, 1914, 1918. In the illustrated embodiment, the electronic switches 1910-1920 include MOSFETs. In other embodiments, other types of electronic switches may be used, such as Bipolar Junction Transistors (BJTs), insulated Gate Bipolar Transistors (IGBTs), and other types of electronic switches. In addition, each electronic switch 1910 to 1920 is connected in parallel with body diodes 1930, 1932, 1934, 1936, 1938, and 1940, respectively.

In the diagram of fig. 19, each phase of motor 1850 is represented by an inductor, resistor, and voltage source. Since motor 1850 is a three-phase motor, FIG. 19 shows three inductors 1904a-c, three resistors 1906a-c, and three voltage sources 1902a-c. Each inductor 1904a-c represents a motor winding for each phase of motor 1850. Each resistor 1906a-c represents a motor winding for each phase of motor 1850. Each voltage source 1902a-c represents a back electromagnetic force (e.g., back emf) generated in each phase. Back emf is generated by the rotation of the rotor magnets to induce current in the stator windings. In addition, power switching network 1900 includes a brake switch 1975 connected in series with a brake resistor 1970. A brake switch 1975 and a brake resistor 1970 are connected in parallel with the first phase 1950, the second phase 1952, and the third phase 1954 of the motor 1850.

Power switch network 1900 receives power from battery pack 78 (via battery pack interface 1885). The battery pack 78 is represented by a power supply 1901 connected in series with a resistor 1922 and an inductor 1924 representing the internal resistance and internal inductance of the battery pack interface 1885, the battery pack 78, or both. In addition, the power supply 1901 is connected in series with a parallel combination of a diode 1926 and a switch 1927. The diode 1926 and switch 1927 control the flow of current from the power supply 1901. For example, the switch 1927 may be switched between a conductive state and a non-conductive state. Switch 1927 may be controlled based on actuation of trigger 50. For example, in some embodiments, the controller 1800 controls the state of the switch 1927 based on the condition of the trigger 50. In some embodiments, when trigger 50 is pressed, switch 1927 is closed by controller 1800 and when trigger 50 is released, switch 1927 is open. In some embodiments, switch 1927 serves as trigger switch 1858.

When the switch 1927 is in the on-state, current may flow bi-directionally to and from the power source 1901. However, when the switch 1927 is in a non-conductive state, current (e.g., regeneration current) may only flow to the power supply 1901 through the diode 1926. In some embodiments, diode 1926 is not provided. As shown in fig. 19, a capacitor 1928 is connected in parallel with power supply 1901. The capacitor 1928 smoothes the voltage from (and to) the power supply 1901.

In addition, the controller 1800 controls the state of each of the electronic switches 1910 to 1920 in the power switch network 1900. To drive motor 1850 in the forward direction, controller 1800 sets switch 1927 to an on-state and enables high-side electronic switch 1912 and low-side electronic switch 1914. As shown in fig. 19, the high side electronic switch 1912 is on a first side of the first phase 1950 of the motor 1850 and the low side electronic switch 1914 is on a second side of the first phase 1950. In such a configuration, the first phase 1950 of the motor 1850 is connected such that the back emf has an opposite polarity relative to the power supply 1901. Accordingly, when the controller 1800 maintains the first high-side electronic switch 1912 and the first low-side electronic switch 1914 in a conductive state, the back emf reduces the total power provided to the motor 1850. In other words, the motor current is set by dividing the difference between the voltage from the power supply 1901 and the back electromotive force by the resistance of the motor 1850.

The controller 1800 determines which of the high-side electronic switches 1912, 1916, 1920 and the low-side electronic switches 1910, 1914, 1918 to place in a conductive state based on the position of the rotor of the motor 1850 relative to the stator. In particular, each activation of the pair of high-side electronic switches 1912, 1916, 1920 and the low-side electronic switches 1910, 1914, 1918 rotates the motor 1850 by approximately 120 degrees. When the motor 1850 rotates approximately 60 degrees, the controller 1800 deactivates one pair of electronic switches and enables a different pair of electronic switches to energize the different phases of the motor 1850. In particular, the controller 1800 enables the first high-side electronic switch 1912 and the first low-side electronic switch 1914 to drive the first phase 1950 of the motor 1850 in a forward direction. The controller 1800 enables the second high-side electronic switch 1916 and the second low-side electronic switch 1918 to drive the second phase 1952 of the motor 1850 in a forward direction, and the controller 1800 enables the third high-side electronic switch 1920 and the third low-side switch 1910 to drive the third phase 1954 of the motor 1850 in a forward direction. Switches 1910 to 1920 may be driven by controller 1800 using Pulse Width Modulation (PWM) control signals having a duty cycle. During each phase, the controller 1800 may set the current supplied to the motor 1850 (and thus the speed and torque) by adjusting the duty cycle of the PWM control signal to one or both of the active switches.

To brake the motor 1850, the controller 1800 controls a brake switch 1975 to direct motor current through a brake resistor 1970. Fig. 20 provides a flowchart illustrating a method 2000 of braking the motor 1850. The method 2000 is performed by the controller 1800. At block 2005, the controller 1800 drives the motor 1850 in response to actuation of the trigger 50. For example, the controller 1800 detects actuation of the trigger 50 based on a trigger signal from the trigger switch 1858. The controller 1800 controls the switch 1927 to an on-state and controls the high-side electronic switches 1912, 1916, 1920 and the low-side electronic switches 1910, 1914, 1918 to drive the motor 1850. At block 2010, the controller 1800 detects the release of the trigger 50. For example, the trigger signal from trigger switch 1858 no longer indicates that trigger 50 is actuated.

At block 2015, in response to release of the trigger 50, the controller 1800 de-drives the motor 1850. For example, the controller 1800 controls the switch 1927 to a non-conductive state to stop providing power to the motor 1850. In some embodiments, the controller 1800 allows the motor 1850 to coast by stopping the power to the motor 1850. At block 2020, controller 1800 determines whether a predetermined time period is met. For example, the controller 1800 allows the motor 1850 to coast for a predetermined period of time.

The predetermined period of time may be, for example, 10 milliseconds, 30 milliseconds, 50 milliseconds, 100 milliseconds, etc. If the predetermined period of time is not met (at block 2020), the controller 1800 continues to allow the motor to coast. If the predetermined period of time is met, the controller 1800 proceeds to block 2025.

At block 2025, the controller 1800 initiates braking of the motor 1850. For example, the controller 1800 controls the brake switch 1975 to provide motor current to the brake resistor 1970. The motor current may be, for example, a current generated by a back emf of the motor 1850. In some embodiments, the controller 1800 uses PWM signals to control "harshness" to control the brake switch 1975, or to control the amount of force generated by braking of the motor 1850. For example, the controller 1800 may initially have a low duty cycle (e.g., 50%) to prevent the drive belt 162 from slipping due to sudden braking operations. The braking force is then increased by increasing the duty cycle of the PWM signal used to control the brake switch 1975. For example, the duty cycle may be increased from 50% to 75%. In some embodiments, the duty cycle of the PWM signal is controlled based on the value of the motor current sensed by the current sensor 1875. As the motor current decreases, the duty cycle of the PWM signal is controlled by the controller 1800 to increase the braking force.

In some embodiments, the controller 1800 controls the brake switch 1975 to brake the motor 1850 until the motor 1850 is completely stopped. In other embodiments, the controller 1800 detects actuation of the trigger 50 while braking the motor 1850. Fig. 21 illustrates a method 2100 of driving a motor 1850. Method 2100 is performed by controller 1800. At block 2105, the controller 1800 detects actuation of the trigger 50 while the motor 1850 is being braked. For example, the controller 1800 receives a trigger signal from the trigger switch 1858 while controlling the brake switch 1975 to brake the motor 1850. At block 2110, the controller 1800 releases the brake of the motor 1850 in response to actuation of the trigger 50. For example, the controller 1800 stops controlling the brake switch 1975. Accordingly, the controller 1800 allows the motor 1850 to coast.

At block 2115, the controller 1800 determines whether a predetermined time period has been met. For example, the controller 1800 allows the motor 1850 to coast for a predetermined period of time. The predetermined period of time may be, for example, 10 milliseconds, 30 milliseconds, 50 milliseconds, 100 milliseconds, etc. If the predetermined period of time is not met (at block 2115), the controller 1800 continues to allow the motor to coast. If the predetermined period of time is met, the controller 1800 proceeds to block 2120. At block 2120, the controller 1800 drives the motor 1850.

In some embodiments, the controller 1800 monitors the voltage of each phase (e.g., first phase 1950, second phase 1952, third phase 1954) of the motor 1850 using a resistive divider circuit. Specifically, a resistive divider circuit is located on each phase node. The controller 1800 monitors the voltages associated with each phase node separately. Based on the voltage provided to the controller 1800, the controller 1800 may determine whether any of the high-side electronic switches 1912, 1916, 1920 and/or any of the low-side electronic switches 1910, 1914, 1918 are shorted.

Fig. 22 provides a method 2200 for performing a protection operation in response to a shorted motor phase. Method 2200 is performed by controller 1800. At block 2205, the controller 1800 monitors the phase voltage of each motor phase. As described above, the inputs of the resistive divider circuits located on each phase node may provide an input voltage to the controller 1800. In some embodiments, voltage sensor 1870 provides a voltage signal to controller 1800 indicative of the phase voltage of each motor phase.

At block 2210, the controller 1800 determines whether the phase voltage of any motor phases is less than or equal to a voltage threshold. If the phase voltage of any motor phase is not less than or equal to the voltage threshold, the controller 1800 returns to block 2205 and continues to monitor the phase voltage of each motor phase. If the phase voltage of any motor phase is less than or equal to the voltage threshold, the controller 1800 proceeds to block 2215. At block 2215, the controller 1800 performs a protection operation on the saw 10. As one example, the controller 1800 stops the drive or braking of the motor 1850 to stop operation of the saw 10.

In addition, many heavy duty power tools (such as concrete saws, rock drills, lawn mowers, etc.) are powered by gas engines. During operation of a gas engine powered power tool, excessive input forces exerted on the power tool or large loads encountered by the power tool may result in drag that impedes further operation of the power tool. For example, a gas engine powered concrete saw that is pushing too fast or too hard to cut concrete may slow or stall its motor due to excessive load (bog-down). The user may sense (e.g., feel and hear) such a stall of the motor, and such a stall is a useful indication that excessive input has been encountered that may potentially damage the power tool. In contrast, a high power electric motor driven power tool, such as that similar to saw 10, does not inherently provide stagnant feedback to the user. Rather, in these high power electric motor driven power tools, excessive loading of the power tool causes the motor to draw excessive current from the power source or battery 78. Drawing excessive current from the battery pack 78 may result in rapid and potentially detrimental wear of the battery pack 78.

Accordingly, in some embodiments, the saw 10 includes an analog stall feature to provide an indication to a user that the saw 10 is overloaded during operation (e.g., as detected from the current level of the motor 1850, the torque level of the motor 1850, etc.). In some embodiments, the controller 1800 performs the method 2300 as shown in fig. 23A to provide simulated stagnation operation of the saw 10 similar to actual stagnation experienced by a gas engine powered power tool.

At block 2305, the controller 1800 controls the power switch network 1855 to provide power to the motor 1850 in response to determining that the trigger 50 has been actuated. For example, controller 1800 provides PWM signals to FETs of power switching network 1900 to drive motor 1850 in accordance with a trigger signal from trigger 50. At block 2310, the controller 1800 detects a load on the saw 10 (e.g., using a current sensor 1875, a torque sensor or transducer included in the auxiliary sensor 1880 that monitors the torque of the motor 1850, etc.). At block 2315, the controller 1800 compares the load to a threshold (e.g., a load threshold). When the load is not greater than the threshold, the controller 1800 returns to block 2310 such that the controller 1800 repeats blocks 2310 and 2315 until the load is greater than the threshold.

When the controller 1800 determines that the load is greater than the threshold, at block 2320, the controller 1800 controls the power switch network 1855 to simulate a stall in response to determining that the load is greater than the threshold. In some embodiments, the controller 1800 controls the power switching network 1855 to reduce the speed of the motor 1850 to a non-zero value. For example, the controller 1800 reduces the duty cycle of the PWM signal provided to the FETs of the power switching network 1855. In some embodiments, the decrease in duty cycle (i.e., the speed of motor 1850) is proportional to the amount the load is above the threshold (i.e., the amount of overload). In other words, the more loaded the saw 10, the more the controller 1800 reduces the speed of the motor 1850. For example, in some embodiments, at block 2320, the controller 1800 determines a difference between the load of the motor 1850 and a load threshold to determine a difference. The controller 1800 then determines the amount of reduction in the duty cycle based on the difference (e.g., using a look-up table).

In some embodiments, at block 2320, the controller 1800 controls the power switching network 1855 in a different or additional manner to provide an indication to the user that excessive loading of the saw 10 is occurring during operation. In such embodiments, the behavior of the motor 1850 may provide a more pronounced indication to the user that excessive loading of the saw 10 is occurring, as compared to the simulated stall described above. As one example, the controller 1800 controls the power switching network 1855 to oscillate between different motor speeds. Such motor control may be similar to a gas engine powered power tool stalling and may provide tactile feedback to the user to indicate that excessive loading of the saw 10 is occurring. In some embodiments, the controller 1800 controls the power switching network 1855 to oscillate between different motor speeds to provide an indication to the user that a very excessive load of the saw 10 is occurring. For example, the controller 1800 controls the power switching network 1855 to oscillate between different motor speeds in response to determining that the load of the saw 10 is greater than a second threshold that is greater than the threshold described above with respect to simulated stall. As another example, in response to determining that the load of the saw 10 has been greater than the threshold described above with respect to the simulated stall for a predetermined time (e.g., two seconds), the controller 1800 controls the power switch network 1855 to oscillate between different motor speeds. In other words, the controller 1800 may control the power switching network 1855 to simulate a stall when an excessive load of the saw 10 is detected, and may control the power switching network 1855 to simulate a stall when the excessive load extends or increases beyond a second threshold.

With respect to any of the embodiments described above with respect to block 2320, other characteristics of the saw 10 and motor 1850 may provide an indication to a user that excessive loading of the saw 10 is occurring (e.g., tool vibration, resonating sound of the shaft of the motor 1850, and sound of the motor 1850). In some embodiments, these characteristics change when the controller 1800 controls the power switching network 1855 to simulate a stall or oscillate between different motor speeds (as described above).

In some embodiments, after controller 1800 controls power switching network 1855 to simulate a stall (at block 2320), controller 1800 performs method 2350 as shown in fig. 23B. At block 2355, which is similar to block 2310, the controller 1800 detects the load on the saw 10. At block 2360, the controller 1800 compares the load on the saw 10 to a threshold. For example, the controller 1800 compares the motor current to a threshold. When the load remains above the threshold, the controller 1800 returns to block 2315 such that the controller 1800 repeats blocks 2315 through 2360 until the load drops below the threshold. In other words, the controller 1800 continues to simulate a stall until the load drops below the threshold. The repetition of blocks 2315 through 2360 allows the controller 1800 to simulate stall differently as the load changes, but remains above a threshold (e.g., proportional adjustment of the duty cycle of PWM provided to the FET as previously described).

When the load on the saw 10 drops below a threshold (e.g., in response to a user pulling the saw 10 off a work surface), the controller 1800 controls the power switch network 1855 to cease the simulation stall and operate according to the actuation of the trigger 50 (block 2365). In other words, the controller 1800 controls the power switching network 1855 to increase the speed of the motor 1850 from a reduced analog stall speed to a speed corresponding to the trigger signal from the trigger 50. For example, the controller 1800 increases the duty cycle of the PWM signal provided to the FETs of the power switching network 1855. In some embodiments, the controller 1800 gradually ramps up the speed of the motor 1850 from a reduced analog stall speed to a speed corresponding to the trigger signal from the trigger 50. The controller 1800 then returns to block 2305 to allow the controller 1800 to continue monitoring the saw 10 for an overload condition. Although not shown in fig. 23A and 23B, as represented by the above description of trigger 50, during execution of any of the blocks in methods 2300 and 2350, controller 1800 may cease providing power to motor 1850 in response to determining that trigger 50 is no longer actuated (i.e., has been released by a user), or may provide power to motor 1850 to cease rotating (e.g., brake).

In some embodiments, while simulating a stall at block 2320, the load on the saw 10 (indicated by the motor current) may continue to increase instead of decreasing below the load threshold. Accordingly, while simulating a stall, the controller 1800 may compare the load to a second threshold. If the load exceeds a second threshold (e.g., the motor current becomes greater than the second threshold), the controller 1800 performs a guard operation to stop driving the motor 1850. The second threshold may be, for example, 60 amps, 70 amps, 80 amps, etc.

The indicator 1845 may be configured to provide information related to the performance of the saw 10. Fig. 24 provides a method 2400 for providing a performance indication for the saw 10. Method 2400 is performed by controller 1800. At block 2405, the controller 1800 enables the motor 1850. The motor 1850 may be enabled in response to a user depressing the trigger 50 of the saw 10, which causes the controller 1800 to control the power switch network 1855 to provide power to the motor 1850.

At block 2410, the controller 1800 detects the motor current using the current sensor 1875. At block 2415, the controller 1800 determines a current level based on the motor current. For example, the controller 1800 compares the detected motor current to a range of motor current thresholds to determine the current level. As one example, the motor current threshold is 20%, 40%, 60%, 80% and 100% of the maximum allowable motor current. The maximum allowable motor current may be the maximum current that the battery pack 78 may discharge without damaging the battery pack 78 or the saw 10. This maximum battery current may be selected as the maximum allowable motor current.

In some embodiments, the amount of expected motor current may vary based on the voltage of the battery pack 78. In these embodiments, the controller 1800 may weight the measured current value using the battery voltage measurements. For example, the expected motor current may be higher when the battery pack 78 has a first, higher voltage (e.g., when fully charged) than when the battery pack 78 has a second, lower voltage (e.g., after the battery pack 78 is partially depleted using the saw 10). Accordingly, the controller 1800 may determine the battery voltage at block 2410 and weight the detected current by multiplying the detected current by a value inversely proportional to the voltage of the battery pack 78. Thus, in some embodiments, the motor current detected in block 2410 is an adjusted current weighted based on the voltage of the battery pack 78. Alternatively, in another embodiment, the voltage of the battery pack 78 is used to adjust the motor current threshold. For example, the motor current threshold is multiplied by a value that is inversely proportional to the voltage of the battery pack 78. In the foregoing description, the term "motor current" is used to describe both the detected motor current and the regulated motor current. Similarly, the term "motor current threshold" is used to describe both a motor current threshold and an adjusted motor current threshold.

As described above, the controller 1800 determines the current level by comparing the motor current to a motor current threshold. For example, when the motor current is below 20% of the motor current threshold, the controller 1800 determines that the motor current is at "current level 1". When the motor current is above 20% of the current threshold but below 40% of the motor current threshold, the controller 1800 determines that the motor current is at "current level 2". Similarly, a motor current between 40% and 60% of the motor current threshold corresponds to "current level 3", a motor current between 60% and 80% of the motor current threshold corresponds to "current level 4", a motor current between 80% and 90% of the motor current threshold corresponds to "current level 5", a motor current between 90% and 100% of the motor current threshold corresponds to "current level 6", and a motor current higher than 100% of the motor current threshold corresponds to "current level 7". In some embodiments, other linear or non-linear thresholds are used for the current levels, and may include more or less current levels than those provided above.

At block 2420, the controller 1800 controls the indicator 1845 to provide an indication corresponding to the current level. In one embodiment, a lookup table may be stored in memory 1825 that maps current levels to indications. For example, fig. 26 illustrates a lighting sequence of an indicator 1845 configured as a plurality of LED strips. The controller 1800 provides control signals to the LED strip based on the indication corresponding to the current level. In another embodiment, the indicator 1845 includes a single LED configured to provide an indication of motor current. To indicate motor current by a single LED, the controller 1800 may change the brightness of the LED (e.g., dim light corresponds to motor current between 20% and 40% of the motor current threshold, and bright light corresponds to motor current between 90% and 100% of the motor current threshold), may change the color of the LED (e.g., green light corresponds to motor current between 20% and 40% of the motor current threshold, and red light corresponds to motor current between 90% and 100% of the motor current threshold), and so forth. After providing the indication, the controller 1800 returns to detecting the next instance of motor current and repeats blocks 2410, 2415, 2420 until an input is detected to deactivate the motor 1850 (e.g., release the trigger 50).

Fig. 25 provides a flowchart illustrating an example method 2500 for providing an indication of performance of saw 10. Method 2500 is performed by controller 1800. At block 2505, the controller 1800 enables the motor 1850. As described above, motor 1850 may be activated in response to a user pressing trigger 50.

At block 2510, the controller 1800 detects one or more parameters of at least one of the battery pack 78 and the saw 10. For example, the controller 1800 communicates with a microprocessor of the battery pack 78 to determine the state of charge, temperature, etc. of the battery pack 78. In addition, the controller 1800 may use auxiliary sensors 1880 to detect temperature, pressure, torque, etc. of the saw 10. At block 2515, the controller 1800 determines system performance based on one or more parameters. The controller 1800 may determine system performance by providing different weights to one or more parameters and combining the weighted parameters using known techniques. The system performance may be modeled after the industry standard reference combines one or more parameters detected to predict the life of the saw 10.

At block 2520, the controller 1800 determines a system performance level based on the system performance. For example, the controller 1800 compares system performance to a range of system performance thresholds to determine a system performance level. In one example, the system performance thresholds are 20%, 40%, 60%, 80% and 100% of the maximum allowable system performance. The maximum allowable system performance may be the maximum of the weighting parameters that the saw 10 may operate without damaging the battery pack 78 or the saw 10. The manufacturer may provide maximum system performance that allows secure operation. The maximum security system performance may be selected as the maximum allowable system performance. In another example, the maximum allowable system performance may be a user-defined system performance level. The user may provide inputs to the saw 10 defining the performance level of the system. In response to user input, the saw 10 stores a user-defined system performance level as a maximum allowable system performance.

As described above, the controller 1800 determines the system performance level by comparing the motor current to a motor current threshold. For example, when the system performance is below 20% of the system performance threshold (i.e., the system performance does not meet the first system performance threshold), the controller 1800 determines that the system performance is at "performance level 1". When the system performance is above 20% of the system performance threshold but below 40% of the system performance threshold (i.e., the system performance meets the first system performance threshold and does not meet the second system performance threshold), the controller 1800 determines that the motor current is at "performance level 2". Similarly, a system performance between 40% and 60% of the system performance threshold corresponds to "performance level 3", a system performance between 60% and 80% of the system performance threshold corresponds to "performance level 4", a system performance between 80% and 90% of the system performance threshold corresponds to "performance level 5", a system performance between 90% and 100% of the system performance threshold corresponds to "performance level 6", and a system performance higher than 100% of the system performance threshold corresponds to "performance level 7". In some embodiments, other linear or nonlinear thresholds are used for the system performance level, and may include more or less system performance levels than those provided above. Further, the system performance level may be defined by a user of the saw 10. For example, a user may provide inputs to the saw 10 defining various system performance levels corresponding to the described system performance levels.

At block 2525, the controller 1800 provides an indication corresponding to the system performance level. In one embodiment, the lookup table may be stored in memory 1825 that maps performance levels to indications. For example, fig. 27 illustrates a lighting sequence of an indicator 1845 configured as a plurality of LED strips. The controller 1800 provides control signals to the LED bars based on the indication corresponding to the system performance level. In another embodiment, the indicator 1845 includes a single LED configured to provide an indication of system performance. To indicate system performance by a single LED, the controller 1800 may change the brightness of the LED (e.g., dim light corresponds to system performance between 20% and 40% of the system performance threshold, and bright light corresponds to system performance between 90% and 100% of the system performance threshold), may change the color of the LED (e.g., red light corresponds to system performance between 20% and 40% of the system performance threshold, and green light corresponds to system performance between 90% and 100% of the system performance threshold), and so forth. After providing the indication, the controller 1800 returns to detecting the next instance of motor current and repeats blocks 2510, 2515, 2520, 2525 until an input is detected to deactivate the motor 1850 (e.g., release the trigger 50).

Although the utility model has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the scope and spirit of one or more independent aspects of the utility model as described.

Various features of the utility model are set forth in the appended claims.

Claims

1. A power tool, comprising:

a housing;

a trigger;

a motor supported within the housing;

a saw blade interconnected with the housing by a support arm and drivably coupled to the motor;

a main handle integrally formed with the housing;

an auxiliary handle coupled to the housing and disposed between the saw blade and the main handle;

a battery receptacle defined by the housing and positioned below the main handle, the battery receptacle configured to receive a battery pack to supply current to the motor; and

a splash guard integrally formed with the housing and positioned between the battery receptacle and the saw blade.

2. The power tool of claim 1, wherein the battery receptacle includes a first wall parallel to a surface of the housing and a second wall oriented obliquely relative to the first wall.

3. The power tool of claim 2, wherein the first wall defines a first tilt angle with respect to a longitudinal axis defined by the support arm, and wherein the second wall defines a second tilt angle with respect to the longitudinal axis of the support arm.

4. The power tool of claim 3, wherein the first tilt angle is 140 degrees, and wherein the second tilt angle is 80 degrees.

5. The power tool of claim 2, wherein the first wall is oriented obliquely with respect to a handle axis defined by the main handle.

6. The power tool of claim 5, wherein the first wall defines an angle of 34 degrees with respect to the handle axis.

7. The power tool of claim 1, wherein the saw blade defines an origin at a center of the saw blade, and wherein a center of gravity of the power tool is located rearward of the origin.

8. The power tool of claim 1, wherein the splash guard extends in a direction opposite the support arm and at least partially defines the battery receptacle.

9. The power tool of claim 1, wherein the main handle extends from the rear portion of the housing in a direction opposite the support arm.

10. The power tool of claim 1, further comprising a drive assembly configured to drivably couple the saw blade to the motor, the drive assembly comprising:

a drive pulley fixed to an output shaft of the motor,

a driven pulley drivably coupled to the drive pulley by a belt,

a main shaft fixed to the driven pulley, and

a clamp assembly configured to secure the saw blade to the spindle.

11. A power tool, comprising:

a housing;

a motor supported within the housing;

a main handle coupled to the housing, the main handle having a front end proximate the saw blade and an opposite rear end;

an auxiliary handle disposed between the saw blade and the main handle; and

a harness is removably coupled to the main handle at a first attachment point at a rear end of the main handle and at a second attachment point on the support arm.

12. The power tool of claim 11, wherein the harness includes a first end and a second end opposite the first end, and wherein the first end and the second end of the harness each have a securing member configured to be coupled to the first attachment point and the second attachment point, respectively.

13. The power tool of claim 12, wherein the first attachment point and the second attachment point each define a recess having a stem.

14. The power tool of claim 12, wherein the harness includes a shoulder pad configured to slide between a first end and a second end of the harness.

15. The power tool of claim 11, further comprising a battery receptacle defined by the housing and positioned below the main handle, the battery receptacle configured to receive a battery pack to supply current to the motor.

16. The power tool of claim 11, further comprising a drive assembly configured to drivably couple the saw blade to the motor, the drive assembly comprising:

a drive pulley fixed to an output shaft of the motor,

a driven pulley drivably coupled to the drive pulley by a belt,

a main shaft fixed to the driven pulley, and

a clamp assembly configured to secure the saw blade to the spindle.

17. A power tool configured to be supported by a cart, the cart including a frame, a mounting assembly securing the power tool to the frame, and a remote actuation system having a first electrical connector, a cart control unit, and a wire configured to interconnect the first electrical connector with the cart control unit, the remote actuation system being operable to enable and disable the power tool when the power tool is secured to the frame, the power tool comprising:

A housing;

a motor supported within the housing;

a saw blade drivably coupled to the motor;

a trigger;

a saw control unit supported within the housing and configured to activate and deactivate the motor in response to a first input control signal from the trigger; and

a second electrical connector in communication with the saw control unit and configured to be electrically connected to the first electrical connector of the cart,

wherein a second input control signal is transmitted from the cart control unit to the saw control unit through the wire via the first and second electrical connectors to selectively activate the motor and the saw blade and change rotational speeds of the motor and the saw blade.

18. The power tool of claim 17, wherein the rotational speed of the motor and the saw blade varies according to the extent to which the throttle lever of the remote actuation system pivots.

19. The power tool of claim 17, wherein the second electrical connector is disposed on a rear end of the housing.

20. The power tool of claim 17, wherein the power tool is a dicing saw.

21. A power tool, comprising:

a housing;

a trigger;

a motor supported within the housing;

a battery receptacle configured to receive a battery pack to supply current to the motor; and

a controller connected to the trigger, the motor, and the battery receptacle, the controller configured to:

the motor is driven in response to actuation of the trigger,

releasing the drive of the motor to allow the motor to coast for a first predetermined period of time in response to the release of the trigger, and

the motor is braked in response to the first predetermined period of time being met.

22. The power tool of claim 21, wherein the controller is further configured to:

detecting actuation of the trigger while braking the motor;

releasing the brake of the motor to allow the motor to coast for a second predetermined period of time in response to actuation of the trigger; and

the motor is driven in response to the second predetermined period of time being met.

23. The power tool of claim 21, further comprising:

A voltage sensor configured to sense a phase voltage of a phase of the motor,

wherein the controller is connected to the voltage sensor, and wherein the controller is further configured to:

the phase voltage is monitored and the phase voltage is measured,

comparing the phase voltage with a voltage threshold, and

in response to the phase voltage meeting the voltage threshold, a protection operation is performed.

24. The power tool of claim 23, wherein the voltage sensor is a resistive divider circuit configured to sense a short of a phase of the motor.

25. The power tool of claim 21, further comprising:

a current sensor configured to sense a motor current,

wherein the controller is connected to the current sensor, and wherein the controller is further configured to:

detecting a load on the saw blade based on the motor current,

comparing the load with a load threshold, and

in response to the load being greater than or equal to the load threshold, a stagnation of the saw blade is simulated.

26. The power tool of claim 25, wherein to simulate a stagnation of the saw blade, the controller is configured to:

The duty cycle of the pulse width modulated signal used to drive the motor is reduced.

27. The power tool of claim 21, further comprising:

a current sensor configured to sense a motor current; and

one or more indicators configured to indicate a condition of the power tool,

wherein the controller is connected to the current sensor and the one or more indicators, and wherein the controller is further configured to:

the motor current is detected by the current sensor,

determining a current level based on the motor current, and

an indication corresponding to the current level is provided using the one or more indicators.

28. A dicing saw, comprising:

a housing;

a motor supported within the housing;

a main handle coupled to the housing, the main handle having a trigger and having a front end proximate the saw blade opposite the rear end;

an auxiliary handle disposed between the saw blade and the main handle; and

An electronic control unit supported within the housing and configured to activate and deactivate the motor in response to an input control signal from the trigger, the electronic control unit comprising a heat sink having a plurality of fins defining channels between adjacent fins such that a first airflow path flows through the channels during operation of the motor,

wherein each of the fins has a corrugated surface.

29. The dicing saw of claim 28, wherein the electronic control unit further comprises a pair of resistors disposed below the heat sink and mounted on respective resistor heat sinks, the resistor heat sinks being spaced apart from one another so as to form a gap therebetween.

30. The dicing saw of claim 29, wherein the second air flow path is configured to flow through the gap formed between the resistor heat sinks.

31. The dicing saw of claim 29, wherein the resistor heat sinks are interconnected by a bracket.