Output element and power tool

Abstract

An output member (112) configured to transmit rotation and torque from a motor (104) of a power tool (100) to a working member (108) of the power tool (100) configured to contact a workpiece, the output member (112) comprising: a hub (128) designed to be rotatably driven about a rotational axis (140) by the motor (104) of the power tool (100), an outer shell (132) adapted to be coupled to the working element (108) of the power tool (100); and an insulator (136) disposed between the hub (128) and the outer shell (132) and configured to electrically isolate the hub (128) from the outer shell (132); characterized in that the hub (128) comprises a main body (144) and a plurality of spokes (148) formed integrally with the main body (144), and the insulator (136) is in direct contact with the main body (144) and each spoke (148) of the plurality of spokes (148).

Description

AREA

[0001] This application relates to an output element and a power tool. BACKGROUND

[0002] Many power tools are manufactured to facilitate forming a workpiece into a desired shape. One such power tool is a table saw. Table saws pose a safety hazard because the table saw blade is typically very sharp and moves at high speed. Accordingly, serious injuries, such as severed fingers and deep lacerations, can occur almost instantly. Several different safety systems have been developed for table saws in response to the dangers inherent in an exposed blade moving at high speed. One such safety system is a blade guard. Blade guards movably enclose the saw blade, providing a physical barrier that must be moved before the rotating blade is exposed.Although blade guards are effective in preventing some injuries, a user's finger is still in proximity to the moving blade, especially when attempting to secure a workpiece when the table saw is being used to shape the workpiece.

[0003] Accordingly, detection or sensing systems have been developed for use with various types of manufacturing equipment and power tools. Such detection systems are operable to trigger a response device by detecting or sensing the proximity or contact of an operator's limbs with a piece of equipment. For example, existing capacitive contact sensing systems in table saws detect contact between the operator and the blade.

[0004] In particular, safety systems for table saws have been developed to stop the blade when a user's hand approaches or touches the blade. Various stopping devices have been developed, including braking devices that are physically inserted into the teeth of the blade. Generally, upon detection of a person near the blade, a signal is processed and sent to a braking mechanism to stop blade rotation within a short period of time. One such system is disclosed in U.S. Patent No. 8,943,937, the disclosure of which is incorporated herein by reference in its entirety. Another such system is disclosed in U.S. Patent No. 9,387,598, the disclosure of which is incorporated herein by reference in its entirety. Other systems utilize a mechanical or electrical brake.

[0005] In many of these security systems, electrical power is supplied to a drive element that drives the rotational movement of the blade, and electrical power is also supplied to the blade to generate a signal indicating contact between the person and the blade. Therefore, it is necessary to separate the electrical power supplied to the drive element and the electrical power supplied to the blade. However, it is difficult to combine mechanical strength to transmit rotation and torque from the drive element to the blade with dielectric properties to electrically separate the electrical power supplied to the drive element from the electrical power supplied to the blade.

[0006] What is needed, therefore, is a connection between a drive element and a work element, such as a blade, that is capable of transmitting rotation and torque from the drive element to the work element, and is also capable of electrically isolating electrical energy provided to the drive element from electrical energy provided to the work element.

[0007] Couplings are also known from the prior art, such as those disclosed in US 2003 0 131 703 A1, US 2015 0 314 409 A1, CN 2 04 226 465 U, DE 10 2013 007 126 A1 and DE 10 2014 204 590 A1. SUMMARY

[0008] The present invention provides an output element having the features of claim 1 and a power tool having the features of claim 10. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows a partial exploded view of a power tool including an output member configured to transmit rotation and torque from a motor of the power tool to a working element of the power tool. Fig. Figure 2A shows a front plan view of an output element comprising a hub, an insulator and an outer shell, which is suitable for use in the Fig. 1 shown power tool. Fig. Figure 2B shows a front perspective view of the output element of Fig. 2A. Fig. Figure 3A shows a front perspective view of an embodiment of a hub suitable for use in the Fig. 2A and Fig. 2B shown output element. Fig. Figure 3B shows a front perspective view of an embodiment of an outer shell suitable for use in the Fig. 2A and Fig. 2B shown output element. Fig. Figure 4 shows a front perspective view of another output element comprising a hub, an insulator and an outer shell, which is suitable for use in the Fig. 1 shown power tool. Fig. Figure 5A shows a front perspective view of an embodiment of a hub suitable for use in the Fig. 4 shown output element. Fig. Figure 5B shows a front perspective view of an embodiment of an insulator suitable for use in the Fig. 4 shown output element. Fig. Figure 5C shows a front perspective view of an embodiment of an outer shell suitable for use in the Fig. 4 shown output element. Fig. Figure 6 shows a front perspective view of another embodiment of an output member designed for use in a power tool. Fig. Figure 7 shows a front perspective view of another embodiment of an output member designed for use in a power tool. Fig. Figure 8 shows a front perspective view of another embodiment of an output member designed for use in a power tool. Fig. Figure 9A shows a schematic view of an alternative form of an outer element. Fig. Figure 9B shows a schematic view of an alternative form of a hub corresponding to the alternative form of the outer element of Fig. 9A is complementary. Fig. Figure 9C shows a schematic view of an alternative form of insulator disposed between the outer member of Fig. 9A and the hub of Fig. 9B is arranged. Fig. Figure 10A shows the example shape of the spokes and the complementary shaped cutouts used in Fig. 9A to 9C. Fig. Figure 10B shows another alternative shape of the spokes and the complementary shaped cutouts used in Fig. 9A to 9C. Fig. Figure 11A shows another alternative form of the outer element of Fig. 9A. Fig. Figure 11B shows another alternative shape of the hub of Fig. 9C, which corresponds to the alternative shape of the outer element of Fig. 11A is complementary. DETAILED DESCRIPTION

[0009] To promote an understanding of the principles of the embodiments described herein, reference is now made in the following written description to the drawings and descriptions. These references are not intended to limit the scope of the subject matter. This patent also covers all changes and modifications to the illustrated embodiments, as well as further applications of the principles of the described embodiments, as would normally occur to one skilled in the art to which this document relates.

[0010] As used herein, the term "power tool" refers to any tool having one or more moving parts that are moved by a drive, such as an electric motor, an internal combustion engine, a hydraulic or pneumatic cylinder, and the like. For example, power tools include, but are not limited to, bevel saws, table saws, circular saws, gang saws, jigsaws, band saws, cold saws, cutters, impact drivers, angle grinders, drills, connectors, nail drivers, sanders, trimmers, and router bits. As used herein, the term "working element" refers to a moving part of the power tool that is at least partially exposed during operation of the power tool. Examples of implementations in power tools include, but are not limited to, rotary and gang saw blades, drill bits, router bits, grinding wheels, sanding wheels, and the like.As described below, an output member for use with a power tool is used to transmit rotation and torque generated by the power tool to the work member, and is further configured to electrically isolate electrical energy provided to a drive member of the power tool from electrical energy provided to the work member.

[0011] Fig. 1 shows a power tool 100 according to the present disclosure, including a motor 104, a saw blade 108, and an output member 112. In the illustrated embodiment, the power tool 100 is a table saw; however, in alternative embodiments, the power tool 100 may be another tool configured to perform a process on a workpiece. The motor 104 is powered by an external power source 116 to generate rotation and torque. Accordingly, the motor 104 is a "drive member." In the illustrated embodiment, Fig. 1, the rotation and torque generated by the motor 104 are transmitted to the output member 112, which is configured as a pulley. Therefore, the rotation of the output member 112 drives a belt 120, which rotates another pulley 124 coupled to the saw blade 108. In the embodiment shown in Fig. 1, the saw blade 108 is physically coupled to the motor 104 via the output member 112, the belt 120, and the pulley 124, and the output member 112 is electrically coupled to the motor 104.

[0012] The power tool 100 further includes an automatic braking system configured to stop the transmission of rotation and torque from the motor 104 to the saw blade 108. The automatic braking system provides electrical energy to the saw blade 108 to enable detection of the proximity or contact of an operator's limbs with the saw blade 108. As described in more detail below, the output member 112 includes an isolator configured to electrically separate the electrical energy provided to the output member 112 by the motor 104 from the energy provided to the output member by the saw blade 108.

[0013] As in Fig. 2A and Fig. 2B, the output member 112 includes a hub 128, an outer shell 132, and an insulator 136. The hub 128 is configured to transmit the rotation and torque by the motor 104 (in Fig. 1) so that the hub 128 is rotated about a rotation axis 140. The outer shell 132 is designed in this embodiment to be connected to the saw blade 108 (in Fig. 1) via the belt 120 and the pulley 124. The insulator 136 is disposed between the hub 128 and the outer shell 132 and is configured to electrically isolate the hub 128 from the outer shell 132.

[0014] As in Fig. 3A, the hub 128 includes a main body 144 and a plurality of spokes 148 formed integrally with the main body 144. The spokes 148 project radially outward from the main body 144 in a direction away from the rotation axis 140. The main body 144 is generally shaped as a hollow cylinder centered about the rotation axis 140 and includes a central opening 152 formed about the rotation axis 140 and an outwardly facing main body surface 156 opposite the central opening 152. The outwardly facing main body surface 156 faces away from the rotation axis 140. The hub 128 is made of a metallic material, such as steel. However, in alternative embodiments, the hub 128 may be made of another metallic material having similar mechanical and electrical properties as steel.

[0015] The spokes 148 of the hub 128 include angled, outwardly facing surfaces 160 and an outermost circumferential surface 164 connecting the angled, outwardly facing surfaces 160. The outermost circumferential surfaces 164 of all spokes 148 are formed on a substantially concentric ring about the axis of rotation 140. The spokes 148 are substantially symmetrically shaped such that the angled, outwardly facing surfaces 160 of each spoke 148 meet the outwardly facing main body surface 156 at angles that are mirrored opposite angles, and such that the angled, outwardly facing surfaces 160 of each spoke 148 meet the outermost circumferential surface of the spoke 148 at angles that are mirrored opposite angles.

[0016] The spokes 148 further include notches 168 formed in the outermost circumferential side surface 164 and extending slightly into the angled, outwardly facing surfaces 160. As explained in more detail below, the notches 168 help to firmly couple the insulator 136 to the hub 128 to prevent movement of the insulator 136 with respect to the hub 128 in a direction along the rotational axis 140.

[0017] As in Fig. 3B, the outer shell 132 is generally shaped complementarily to the hub 128. The outer shell 132 is generally shaped as a hollow cylinder centered about the rotation axis 140 and includes a shaped opening formed about the rotation axis 140 and an outwardly facing surface opposite the shaped opening. The outwardly facing surface faces away from the rotation axis 140. In the Fig. 3B, the shaped opening includes cutouts 180 that are generally shaped to complement the spokes 148 of the hub 128. The outer shell 132 is made of a metallic material, such as aluminum. However, in alternative embodiments, the outer shell 132 may be made of another metallic material that has similar mechanical and electrical properties to aluminum.

[0018] The cutouts 180 are formed in an innermost circumferential surface 184 of the outer shell 132 and are generally complementary to the spokes 148 of the hub 128. In particular, the cutouts 180 include angled, inwardly facing surfaces 188 and outermost circumferential surfaces 192. When the hub 128 is received within the outer shell 132, as shown in Fig. 2A and Fig. 2B, the spokes 148 are received within corresponding cutouts 180 such that the outwardly facing main body surface 156 faces the innermost peripheral surface 184 of the outer shell 132, the angled, outwardly facing surfaces 160 of the spokes 148 face the angled, inwardly facing surfaces 188 of the cutouts 180, and the outermost peripheral surfaces 164 of the spokes 148 face the outermost peripheral surface 192 of the outer shell 132.

[0019] The outer shell 132 also includes notches 196 formed in the innermost circumferential surface 184 and extending slightly into the angled, inwardly facing surfaces 188 of the cutouts 180. As explained in more detail below, the notches 196 help to firmly couple the insulator 136 to the outer shell 132 to prevent movement of the insulator 136 with respect to the outer shell 132 in a direction along the rotational axis 140.

[0020] As in Fig. 2A, the insulator 136 is disposed between the hub 128 and the outer shell 132. Therefore, the insulator 136 is formed as a hollow member that includes internal recesses 200 configured to mateably receive the spokes 148 of the hub 128 and external recesses 204 configured to mateably receive the cutouts 180 of the outer shell 132. The insulator 136 is constructed from a dielectric material, such as a plastic material. In alternative embodiments, the insulator 136 may be constructed from various dielectric materials capable of electrically isolating the hub 128 from the outer shell 132.

[0021] The insulator 136 includes a substantially cylindrically shaped hollow inner ring 208 disposed substantially concentrically about the rotational axis 140 and including an inwardly facing inner ring surface 212 and an outwardly facing inner ring surface 216. The inwardly facing inner ring surface 212 is configured to directly contact the outwardly facing main body surface 156 of the hub 128, and the outwardly facing inner ring surface 216 is configured to directly contact the innermost circumferential surface 184 of the outer shell 132.

[0022] The insulator also includes a substantially cylindrically shaped hollow outer ring 220 disposed substantially concentrically about the rotation axis 140 and the inner ring 208. The outer ring 220 includes an inwardly facing outer ring surface 224 and an outwardly facing outer ring surface 228. The inwardly facing outer ring surface 224 is configured to directly contact the outermost peripheral surface 164 of the spokes 148, and the outwardly facing outer ring surface 228 is configured to directly contact the outermost peripheral surface 192 of the outer shell 132.

[0023] The insulator 136 further includes inwardly facing angled surfaces 232 that connect the inwardly facing inner ring surfaces 212 to the inwardly facing outer ring surfaces 224. The inwardly facing angled surfaces 232 are configured to directly contact the angled outwardly facing surfaces 160 of the spokes 148. The insulator 136 further includes outwardly facing angled surfaces 236 that connect the outwardly facing inner ring surfaces 216 to the outwardly facing outer ring surfaces 228. The outwardly facing angled surfaces 236 are configured to directly contact the angled inwardly facing surfaces 188 of the cutouts 180.

[0024] In the Fig. 2A, Fig. 2B, Fig. 3A and Fig. 3B, the insulator 136 is formed between the hub 128 and the outer shell 132. Accordingly, in the embodiment shown in Fig. <h2 style=";text-align:left;direction:ltr">2A,<h2 style=";text-align:left;direction:ltr"> Fig. <h2 style=";text-align:left;direction:ltr"> 2B,<h2 style=";text-align:left;direction:ltr"> Fig. <h2 style=";text-align:left;direction:ltr"> 3A and<h2 style=";text-align:left;direction:ltr"> Fig. 3B, the material from which the insulator 136 is made is also moldable. The insulator 136 is molded between the hub 128 and the outer shell 132 such that the insulator 136 has a uniform thickness T between the hub 128 and the outer shell 132. The insulator 136 is also molded between the hub 128 and the outer shell 132 such that the insulator 136 is formed within the notches 168 formed in the spokes 148. This integration of the insulator 136 into the hub 128 prevents movement of the insulator 136 relative to the hub 126 in a direction along the rotation axis 140. The insulator 136 is also formed between the hub 128 and the outer shell 132 such that the insulator 136 is formed within the notches 196 formed in the outer shell 132.This integration of the insulator 136 into the outer shell 132 prevents movement of the insulator 136 with respect to the outer shell 132 in a direction along the rotation axis 140.

[0025] According to an alternative, in Fig. 4, the hub 128, the outer shell 132, and the insulator 136 may be formed as three separate parts and may subsequently be joined together. In such embodiments, the insulator 136 is not formed between the hub 128 and the outer shell 132. Accordingly, as shown in Fig. 5A, the hub 128 does not include the notches 168, and, as shown in Fig. 5C, the outer shell 132 need not include the notches 196. However, as shown in Fig. 5A, Fig. 5B and Fig. 5C, the hub 128, the insulator 136 and the outer shell 132 are formed in a different manner and, as described above with reference to the embodiments of Fig. 2A, Fig. 2B, Fig. 3A and Fig. 3B.

[0026] In the Fig. 4, the output member 112 may include a retaining ring 240 instead of the notches 168 to prevent relative movement of the insulator 136 and the hub 128 in a direction along the rotation axis 140. Additionally, the output member 112 may include an end plate 244 instead of the notches 196 to prevent relative movement of the insulator 136 and the outer shell 132 in a direction along the rotation axis 140.

[0027] The retaining ring 240 is a flexible ring, made, for example, of metal, and includes a gap 248. By bending the retaining ring 240 to widen the gap 248, the retaining ring 240 can be coupled to a projection 252 on the main body 144 of the hub 128 after the hub 128 has been received within the insulator 136. The retaining ring 240 is disposed substantially concentrically about the rotational axis 140. The retaining ring 240 has a width W sufficient to support the insulator 126 over the inwardly facing inner ring surface 212 (shown in Fig. 2A). Accordingly, the retaining ring 240 prevents movement of the insulator 136 relative to the hub 128 in the direction along the rotation axis 140.

[0028] The end plate 244 is a substantially disc-shaped plate, made, for example, of metal, and including an access opening 256 and a plurality of attachment openings 260. The end plate 244 is shaped to be coupled to the outer shell 132 such that the access opening 256 is disposed substantially concentrically about the rotation axis 140. In other words, the end plate 244 is bonded to the outer shell 132 on a front surface 264 (shown in Fig. 5C) of the outer shell 132 which is perpendicular to the innermost peripheral side surface 184, the angled, inwardly facing surfaces 188 and the outermost peripheral surface 192 of the outer shell 132.

[0029] The access opening 256 is shaped such that the end plate 244 can access the hub 128 or the inwardly facing inner ring 212, the inwardly facing outer ring surface 224, or the inwardly facing angled surfaces 232 (shown in Fig. 2A) of the insulator 136. However, the end plate 244 covers the outwardly facing inner ring surface 216, the outwardly facing outer ring surface 228, and the outwardly facing angled surfaces 236 (shown in Fig. 2A) of the insulator 136 and the front surface 264 of the outer shell 132. Therefore, the end plate 244 prevents movement of the insulator 136 with respect to the outer shell 132 in the direction along the rotation axis 140. The end plate 244 is coupled to the outer shell 132 with fasteners 268 that are received in the mounting openings 260 and in corresponding mounting openings 272 formed in the front surface 264 of the outer shell 132 (shown in Fig. 5C). The fastening devices 268 may, for example, be bolts that are screwably coupled to mating threads provided in the fastening openings 260, 272.

[0030] In the embodiment of the hub 128 shown in Fig. 2B, the central opening 152 includes ribs or teeth configured to mateably couple the hub 128 with corresponding complementary ribs or teeth of the power tool 100. In the Fig. 3A, the central opening 152 of the hub 128 can be threaded to threadably couple the hub 128 to corresponding complementary threads of the power tool 100. As another alternative, as in the embodiment in Fig. 5A, the central opening 152 of the hub 128 may include a key or groove configured to mateably couple the hub 128 to corresponding complementary keys or grooves of the power tool 100. In any of these or other alternative embodiments, the central opening 152 of the hub 128 is configured to mateably receive a portion of the power tool 100 to couple the output member 112 to the power tool 100 such that the output member 112 can transmit rotation and torque generated by the motor 104 of the power tool 100 to the work element, such as the saw blade 108, of the power tool 100.

[0031] The complementary shapes of the hub 128, the insulator 136, and the outer shell 132 of the output member 112 enable the output member 112 to transmit rotation and torque from the motor 104 to the saw blade 108 with robust mechanical strength. Furthermore, the electrically insulating material properties of the insulator 136 electrically isolate the electrical energy in the hub 128 from the electrical energy in the outer shell 132.

[0032] The embodiments of the output element 112 described above and in Fig. 2A to 5C are designed for use in a pulley system such as that used in the power tool 100 of Fig. 1. However, as described below, the output element 112 may also be adapted for use in alternative embodiments.

[0033] As in Fig. 6, an alternative embodiment of an output member 112' is adapted for use in a power tool wherein the outer shell 132' is coupled to the working element, such as the saw blade 108, via engaging ribs or teeth, rather than a pulley system. The output member 112' includes an outer shell 132' having an outer surface 276' including a plurality of ribs or teeth 280' configured to mate with corresponding complementary ribs or teeth to couple the outer shell 132' to the output member.

[0034] As in Fig. 7, another alternative embodiment of an output member 112" is adapted for use in a power tool wherein the outer shell 132" is coupled to the work element, such as a saw blade 108, via a flange, rather than a pulley system. The output member 112" includes an outer shell 132" having a flange 284" integrally formed with the outer shell 132". The flange 284" includes a plurality of mounting apertures 288" adapted to couple the outer shell 132" to the work element.

[0035] As in Fig. 8, in another alternative embodiment, the embodiments of Fig. 6 and Fig. 7 can also be combined in the output member 112'''. Therefore, the output member 112''' includes a hub 128''' and an insulator 136''' coupled to the hub 128''' and axially retained thereon by a retaining ring 240'''. The output member 112''' also includes an outer shell 132''' coupled to the insulator 136''' and axially retained thereon by the end plate 244''' and the fasteners 268'''. The outer shell 132''' of the output member 112''' further includes ribs or teeth 280''' formed on the outer surface 276''' of the outer shell 132''' and a flange 284''' integrally formed with the outer shell 132'''.

[0036] It should be noted that the spokes 148, the cutouts 180 and the insulator 146 may have corresponding shapes different from those shown in the embodiments of Fig. 2A to 8, without changing the operation of the output element 112. For example, as shown in Fig. 9A, Fig. 9B and Fig. 9C, the hub 128, the outer shell 132 and the insulator 136 have a more rounded shape so that the angled, outwardly facing surfaces 160 of the spokes 148 (shown in Fig. 9B) are not substantially planar. Likewise, the corresponding angled, inwardly facing surfaces 188 of the cutouts 180 of the outer shell 132 (shown in Fig. 9A) are not substantially planar. Accordingly, the surfaces of the insulator 136 (shown in Fig. 9C) are designed to mate with the rounded surfaces of the spokes 148 and the cutouts 180 of the hub 128 and the outer shell 132 when the insulator 136 is disposed between the hub 128 and the outer shell 132.

[0037] Fig. 10A and Fig. 10B show a contour that can form the shape of the spokes 148 and the complementary shaped cutouts 180. As in Fig. 10A, the shape may include curves rather than being entirely planar or linear. Alternatively, as shown in Fig. 10B, the shape only includes linear sections.

[0038] Fig. 11A and Fig. 11B show yet another embodiment of corresponding shapes of the outer shell 132 (shown in Fig. 11A) and the hub 128 (shown in Fig. 11B). In this embodiment, the angled, inward-facing surfaces 188 of the cutouts 180 meet the outermost peripheral surface 192 at nearly perpendicular angles. Likewise, the angled, outward-facing surfaces 160 of the spokes 148 meet the outermost peripheral surfaces 164 of the spokes 148 at nearly perpendicular angles.

[0039] Regardless of the shapes of the spokes 148 and the cutouts 180, the shapes are formed to correspond to each other so that the insulator 136 disposed between the hub 128 and the outer shell 132 contacts the outwardly facing surfaces of the hub 128 and the inwardly facing surfaces of the outer shell 132, and the insulator 136 has a uniform thickness T between the hub 128 and the outer shell 132. This configuration provides uniform surfaces for transmitting power between the hub 128, the insulator 136, and the outer shell 132 to provide the output member 112 with the most robust mechanical strength in transmitting rotation and torque from the motor 104 to the saw blade 108 of the power tool 100.

[0040] The foregoing detailed description of the one or more embodiments of the output member for a power tool has been presented herein by way of example and not by way of limitation. It should be understood that there are advantages of certain individual features and functions described herein that may be achieved without the inclusion of other features and functions described herein. Furthermore, it should be understood that various alternatives, modifications, alterations, or improvements to the above-disclosed embodiments and other features and functions, or alternatives thereof, may be combined in any desired manner to form many other embodiments, systems, or applications. Presently unforeseen or unexpected alternatives, modifications, alterations, or improvements thereto may subsequently be made by those skilled in the art, which are also intended to be encompassed by the appended claims.Therefore, the spirit and scope of any appended claims should not be limited to the description of the embodiments incorporated herein.

Claims

[1] An output member (112) configured to transmit rotation and torque from a motor (104) of a power tool (100) to a working member (108) of the power tool (100) configured to contact a workpiece, the output member (112) comprising: a hub (128) designed to be driven by the motor (104) of the power tool (100) to rotate about a rotation axis (140), an outer shell (132) adapted to be coupled to the working element (108) of the power tool (100); and an insulator (136) disposed between the hub (128) and the outer shell (132) and configured to electrically isolate the hub (128) from the outer shell (132); characterized by , that the hub (128) comprises a main body (144) and a plurality of spokes (148) formed integrally with the main body (144), and the insulator (136) is in direct contact with the main body (144) and each spoke (148) of the plurality of spokes (148). [2] The output element (112) of claim 1, wherein the insulator (136) is made of a dielectric material and is in direct contact with the hub (128) and the outer shell (132). [3] The output element (112) of claim 2, wherein the insulator (136) is made of a plastic material. [4] The output element (112) of claim 1, wherein the insulator (136) has a uniform thickness (T) between the hub (128) and the outer shell (132). [5] Output element (112) according to claim 1, wherein: the insulator (136) comprises a plurality of outwardly facing surfaces (216, 228, 236) opposite the spokes (148) and the main body (144) of the hub (128), and the outer shell (132) is in direct contact with each of the outwardly facing surfaces (216, 228, 236) of the insulator (136). [6] Output element (112) according to claim 5, wherein: the outer shell (132) comprises a plurality of inwardly facing surfaces (184, 188, 192) in contact with the outwardly facing surfaces (216, 228, 236) of the insulator (136), and the output member (112) comprises a plurality of grooves (168, 196) formed on at least one of the spokes (148) for engaging the insulator (136) to prevent relative movement of the insulator (136) and the hub (128) along the rotational axis (140), and the inwardly facing surfaces (184, 188, 192) for engaging the insulator (136) to prevent relative movement of the insulator (136) and the outer shell (132) along the rotational axis (140). [7] The output element (112) of claim 1, wherein the insulator (136) is formed between the hub (128) and the outer shell (132). [8] Output element (112) according to claim 1, wherein: the hub (128) and the insulator (136) are formed as separate parts, and the output member (112) further comprises a retaining ring (240) configured to be coupled to the main body (144) of the hub (128) to prevent relative movement of the hub (128) and the insulator (136) along the rotational axis (140). [9] Output element (112) according to claim 1, wherein: the insulator (136) and the outer shell (132) are formed as separate parts, and the output member (112) further comprises a plate (244) configured to be coupled to the outer shell (132) to prevent relative movement of the insulator (136) and the outer shell (132) along the rotation axis (140). [10] Power tool (100) for performing a process on a workpiece, the power tool (100) comprising: a motor (104) designed to generate rotation and torque, a working element (108) designed to be in contact with the workpiece, and an output member (112) configured to transmit the rotation and torque from the motor (104) to the working member (108), the output member (112) comprising: a rotation axis (140), wherein the output element (112) is designed to be driven rotatably about it by the motor (104), a hub (128) adapted to be coupled to the motor (104), an outer shell (132) adapted to be coupled to the working element (108); and an insulator (136) disposed between the hub (128) and the outer shell (132) and configured to electrically isolate the hub (128) from the outer shell (132); characterized by , that the hub (128) comprises a main body (144) and a plurality of spokes (148) formed integrally with the main body (144), and the insulator (136) is in direct contact with the main body (144) and each spoke (148) of the plurality of spokes (148). [11] The power tool (100) of claim 10, wherein the insulator (136) is made of a dielectric material and is in direct contact with the hub (128) and the outer shell (132). [12] The power tool (100) of claim 11, wherein the insulator (136) is made of a plastic material. [13] The power tool (100) of claim 10, wherein the insulator (136) has a uniform thickness (T) between the hub (128) and the outer shell (132). [14] Power tool (100) according to claim 10, wherein: the insulator (136) comprises a plurality of outwardly facing surfaces (216, 228, 236) opposite the spokes (148) and the main body (144) of the hub (128), and the outer shell (132) is in direct contact with each of the outwardly facing surfaces (216, 228, 236) of the insulator (136). [15] Power tool (100) according to claim 14, wherein: the outer shell (132) comprises a plurality of inwardly facing surfaces (184, 188, 192) in contact with the outwardly facing surfaces (216, 228, 236) of the insulator (136), and the output member (112) comprises a plurality of grooves (168, 196) formed on at least one of the spokes (148) for engaging the insulator (136) to prevent relative movement of the insulator (136) and the hub (128) along the rotational axis (140), and the inwardly facing surfaces (184, 188, 192) for engaging the insulator (136) to prevent relative movement of the insulator (136) and the outer shell (132) along the rotational axis (140). [16] The power tool (100) of claim 10, wherein the insulator (136) is formed between the hub (128) and the outer shell (132). [17] Power tool (100) according to claim 10, wherein: the hub (128) and the insulator (136) are formed as separate parts, and the output member (112) further comprises a retaining ring (240) configured to be coupled to the main body (144) of the hub (128) to prevent relative movement of the hub (128) and the insulator (136) along the rotational axis (140). [18] Power tool (100) according to claim 10, wherein: the insulator (136) and the outer shell (132) are formed as separate parts, and the output member (112) further comprises a plate (244) configured to be coupled to the outer shell (132) to prevent relative movement of the insulator (136) and the outer shell (132) along the rotation axis (140).

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