Quick change tool head and hand-held power tool

Abstract

The invention relates to a hand-held power tool (10) comprising a tool housing (16) and a quick-change working head (50). The working head (50) comprises an axial input adapter (52), an axial output adapter (54) and a transmission (56) having a specific transmission ratio (i). It is proposed that the working head (50) contains a magnetic element (58) and that the front portion (16b) of the tool housing (16) contains a corresponding magnetic element (60). When the working head (50) is brought close to the front portion (16b) of the tool housing (16), the magnetic element (58) interacts magnetically with the corresponding magnetic element (60). The magnetic interaction between the magnetic element (58) and the corresponding magnetic element (60) ensures that the working head (50) is firmly fixed in relation to the front portion (16b) of the tool housing (16) in an axial direction which extends parallel to the axis of rotation (30) of the axial input adapter (52).

Description

Technical Field

[0001] This invention relates to a quick-change working head, detachably mounted to the front end of the tool housing of a handheld power tool, particularly a polisher or sander. The working head includes: an axial input adapter detachably connected to the tool shaft of the power tool; an axial output adapter detachably connected to the working element of the power tool, particularly the backplate; and a transmission mechanism with a specific gear ratio. The transmission mechanism is functionally located between the axial input adapter and the axial output adapter and is adapted to rotate the axial output adapter at a given speed, which depends on the rotational speed of the axial input adapter and the gear ratio of the transmission mechanism.

[0002] The present invention also relates to a handheld power tool, particularly a polisher or sander, having a tool housing and a quick-change working head of the type described above, which is detachably connected to the front of the tool housing of the power tool. Background Technology

[0003] The above-mentioned types of quick-change workheads and handheld power tools are known in the prior art, such as the cordless rotary and track polisher called ShineMate EB210 (https: / / shinemate.com / products / info / 73.html) supplied and sold by K &FP Limited (Address: Rooms 13-15, 19th Floor, Nan Fung Centre, 264-298 Castle Road, Tsuen Wan, Hong Kong).

[0004] The so-called "giraffe" shaped quick-change power tool, manufactured and sold by FLEX Elektrowerkzeuge GmbH, located in Steinheim / Murr 71711, Germany, is also described in detail in EP1719581A1. Similar power tools and tools are also found in DE19815443C1.

[0005] What all known quick-change heads and known handheld power tools have in common is that the connection between the head and the front end of the tool is achieved through a mechanical connection. This mechanical connection can be a bayonet connection or a plug-in connection; these are just a few examples. A drawback of known mechanical connections for heads is that connecting or disconnecting the head from the front end of the tool housing is very time-consuming and complex. Summary of the Invention

[0006] Therefore, one object of the present invention is to simplify and speed up the connection and disassembly of the working head and the front end of the tool housing.

[0007] The objective is achieved by a quick-change workhead including the features described in claim 1. Specifically, based on the aforementioned quick-change workhead, a workhead is proposed that includes a magnetic element comprising one or more permanent magnets and / or one or more ferromagnetic elements. The magnetic element is adapted to magnetically interact with a corresponding magnetic element (including one or more permanent magnets and / or one or more ferromagnetic elements) located at the front of the tool housing of a handheld power tool. During attachment of the workhead to the front of the tool housing of the power tool, magnetic interaction is achieved between the magnetic element of the workhead and the corresponding magnetic element at the front of the tool housing. This magnetic interaction ensures that the workhead is securely fixed axially relative to the front of the tool housing, the axial direction extending parallel to the rotation axis of the axial input adapter or the tool shaft, respectively.

[0008] The object of the present invention can also be achieved by a handheld power tool incorporating the features of claim 11. Specifically, starting from the aforementioned handheld power tool, it is proposed that the working head includes a magnetic element comprising one or more permanent magnets and / or one or more ferromagnetic elements; and that the front portion of the tool housing of the handheld power tool also includes a corresponding magnetic element comprising one or more permanent magnets and / or one or more ferromagnetic elements. During attachment of the working head to the front portion of the tool housing, these magnetic elements are adapted to generate a magnetic interaction with the corresponding magnetic element as the working head approaches the front portion of the tool housing. The magnetic interaction between the magnetic elements of the working head and the corresponding magnetic elements of the front portion of the tool housing ensures that the working head can be securely fixed axially relative to the front portion of the tool housing, the axial direction extending parallel to the rotation axis of the axial input adapter or the tool shaft, respectively.

[0009] Preferably, the working head has an adapter housing in which an axial input adapter, an axial output adapter, and a transmission device are rotatably mounted. The adapter housing of the working head is axially and firmly fixed relative to the front of the tool housing by magnetic interaction or magnetic force between the magnetic element of the working head and a corresponding magnetic element at the front of the tool housing. When the adapter housing is firmly fixed relative to the tool housing by magnetic force, it cannot rotate relative to the tool housing about the axis of rotation of the axial input adapter or the tool shaft; that is, the adapter housing is fixed to the tool housing in a torque-resistant manner.

[0010] The working head is detachably held axially relative to the front of the tool housing. To release the working head from the tool housing, it must be pulled axially away from the tool housing, thereby overcoming the magnetic force acting between the magnetic element of the working head and the corresponding magnetic element of the tool housing. The corresponding magnetic element is preferably located on or inside the surface of the front of the tool housing (facing the working head when mounted on the front of the tool housing). Similarly, the magnetic element of the working head is preferably located on or inside the surface of the working head (facing the front of the tool housing when mounted on the front of the tool housing).

[0011] According to a preferred embodiment of the invention, the working head is proposed to include a mechanical positioning device adapted to mechanically interact with a corresponding mechanical positioning device located at the front of the tool housing of a handheld power tool when the working head is mounted to the front of the tool housing. This mechanical interaction between the working head's mechanical positioning device and the corresponding mechanical positioning device at the front of the tool housing holds the working head at a specific angular position relative to the front of the tool housing in a circumferential direction extending in a plane perpendicular to the axis of rotation of the axial input adapter or tool shaft. When the working head is mounted to the front of the tool housing and held axially by magnetic force, the mechanical positioning device also prevents the working head from rotating circumferentially relative to the front of the tool housing.

[0012] At least some of the mechanical positioning devices of the working head and / or at least some of the mechanical positioning devices of the front of the tool housing of the power tool may include one or more initial guide portions that facilitate mechanical contact with each other. Subsequently, as the working head moves further axially forward toward the front of the tool housing, the initial guide portions can guide the working head to a connection position relative to the front of the tool housing. Preferably, in the connection position, the magnetic elements of the working head and the magnetic elements of the front of the tool housing face each other and are arranged opposite each other, thereby creating maximum magnetic force between the magnetic elements of the working head and the magnetic elements of the front of the tool housing. Therefore, the mechanical positioning device can facilitate and accelerate the connection process between the working head and the front of the tool housing.

[0013] Furthermore, it is recommended that the mechanical positioning device of the working head and the corresponding mechanical positioning device at the front of the tool housing each have an extension portion extending only axially, parallel to the rotation axis of the axial input adapter or tool shaft. Therefore, the guiding motion of the working head toward the front of the tool housing to the mounting position is strictly axial linear motion. Of course, this guiding motion may also take other forms, such as helical motion, or constitute part of the helical rotation of the working head relative to the front of the tool housing.

[0014] According to another preferred embodiment of the invention, it is recommended that the transmission ratio i of the transmission device be i>1, particularly preferably i>1.5, preferably i≥2, and particularly preferably i=2.36, thereby reducing the speed of the axial output adapter and increasing its torque relative to the speed and torque of the axial input adapter. This design is particularly advantageous if only small motors, especially those with small outer diameters (typically less torque than large motors), can be used due to limitations in the internal space of the tool housing. Even with such small motors, sufficient torque can be generated as long as the motor speed is high enough. For example, when the transmission ratio i=2 and the maximum motor speed is approximately 5000 rpm, the maximum speed of the axial output adapter or its connected backplate can reach 2500 rpm, while generating sufficient torque for polishing or grinding the desired working surface or workpiece. The transmission device can be designed to reduce the speed of the output adapter relative to the speed of the input adapter, while changing the type or mode of motion of the axial output adapter. For example, the tool shaft and the axial input adapter can rotate, while the axial output adapter can perform one of gear-driven (or forced eccentric) motion, random trajectory (or free eccentric) motion, and trajectory motion.

[0015] Of course, the transmission can also have a transmission ratio of i=1 or i<1. When i=1, the transmission is designed to keep the speed of the input adapter constant, while only changing the motion type or motion of the axial output adapter. For example, the tool shaft and the axial input adapter can perform rotary motion, and the axial output adapter can perform one of the following: gear-driven (or forced eccentric) motion, random trajectory (or free eccentric) motion, and trajectory motion.

[0016] When i < 1, the transmission can be designed to increase the rotational speed of the axial output adapter relative to the axial input adapter. Simultaneously, the torque generated by the output adapter and supplied to the backplate is less than the torque generated by the tool shaft and the input adapter, respectively. This is particularly suitable for high-speed applications that do not require high torque. The transmission can also be designed to increase the rotational speed of the output adapter relative to the input adapter while simultaneously changing the type or motion performed by the axial output adapter. For example, the tool shaft and axial input adapter can perform rotary motion, while the axial output adapter can perform one of the following: gear-driven (or forced eccentric) motion, random trajectory (or free eccentric) motion, or trajectory motion.

[0017] Preferably, the transmission device is designed to convert the rotational motion of the axial input shaft into the rotational motion of the axial output shaft, and the rotational speed of the axial output shaft is different from that of the axial input shaft, wherein the rotational axes of the axial input shaft and the axial output shaft coincide with each other. Therefore, the transmission device is designed to maintain the motion type of the axial input shaft and simply transmit it to the axial output shaft. Preferably, the rotational speed of the axial output shaft is less than the rotational speed of the axial input shaft, i.e., the transmission ratio i > 1, and the torque provided by the axial output shaft and the torque provided to the back plate are respectively greater than the torque provided by the tool shaft of the power tool and the axial input shaft of the working head.

[0018] Preferably, the transmission device is designed to convert the rotational motion of the axial input shaft into the rotational motion of the axial output shaft, and the rotational direction of the axial output shaft is the same as that of the axial input shaft.

[0019] Furthermore, it is suggested that the axial input adapter of the working head include an axial groove having a non-rotationally symmetric internal cross-section comprising a polygon, particularly a square, hexagon, or octagon. The power tool's tool spindle includes a shaft-like distal end having a correspondingly non-rotationally symmetric external cross-section comprising a polygon, particularly a square, hexagon, or octagon. The axial groove of the axial input adapter of the working head is adapted to receive the shaft-like distal end of the power tool's tool spindle axially, thereby establishing a torque-resistant connection between the tool spindle and the axial input adapter.

[0020] Optionally, it is recommended that the axial input adapter of the working head include a shaft-shaped protrusion having a non-rotationally symmetric external cross-section comprising a polygon, particularly a square, hexagon, or octagon. The power tool's tool spindle includes an axial groove having a correspondingly non-rotationally symmetric internal cross-section comprising a polygon, particularly a square, hexagon, or octagon. The shaft-shaped protrusion of the axial input adapter of the working head is adapted to be axially inserted into the axial groove at the distal end of the power tool's tool spindle to establish a torque-resistant connection between the tool spindle and the axial input adapter.

[0021] Preferably, when the working head is connected to the tool housing, the axial input adapter automatically engages with the distal end of the tool spindle in a torque-resistant manner. Therefore, when the adapter housing of the working head is securely fixed magnetically relative to the front of the tool housing (in a torque-resistant manner), torque can be transmitted from the power tool spindle to the input adapter of the working head. The installation and removal of the working head is simple, convenient, and safe.

[0022] In another preferred embodiment of the quick-change working head according to the invention, the axial output adapter of the working head is proposed to include an axial groove with a threaded inner wall. A retaining pin is secured to the top surface of the back plate. The axial distal end of the retaining pin has a threaded outer surface. The axial groove is adapted to receive the distal end of the retaining pin threadedly, thereby establishing a threaded connection between the back plate and the axial output adapter. Free rotation of the output adapter should be prevented when installing / removing the back plate from the axial output adapter. This can be achieved by using a separate tool component that can be inserted into the working head and prevents free rotation of the axial output adapter; or by using an integrated braking or locking device that can be activated or deactivated by the user of the working head or power tool, respectively. This braking or locking device can be integrated into the working head.

[0023] Optionally, the recommended axial output adapter for the working head includes a retaining pin with a axial distal end having a threaded outer surface. An axial groove with a corresponding threaded inner wall is provided on the top surface of the backplate. The axial distal end of the retaining pin is adapted to be threaded into the axial groove of the backplate, thereby establishing a threaded connection between the backplate and the axial output adapter. Attached Figure Description

[0024] Other features and advantages of the invention will become clearer from the following description taken in conjunction with the accompanying drawings. It should be emphasized that each feature shown in the drawings is essential to the invention in itself, even if not explicitly mentioned in the specification. Furthermore, the features shown in the drawings can be combined in any desired manner, even if not explicitly shown in the drawings and not described in the specification. The drawings are as follows:

[0025] Figure 1 A side view of the quick-change working head according to the present invention;

[0026] Figure 2a for Figure 1 The quick-change head shown is a cross-sectional side view, which is transverse to the vertical center axis;

[0027] Figure 2b Example of a backplate for an axial output adapter connected to a working head;

[0028] Figure 3 for Figure 1 A perspective view of the quick-change head shown;

[0029] Figure 4 for Figure 1 The quick-change working tip shown Figure 2a Bottom view of section IV-IV in the image;

[0030] Figure 5 for Figure 1The diagram shown is an exploded view of the quick-change head after it has been partially disassembled.

[0031] Figure 6 A handheld power tool in the form of a polisher or sander according to the invention, which has a quick-change working head according to the invention;

[0032] Figure 7 for Figure 6 A sectional view of the front of the power tool shown. Detailed Implementation

[0033] Figure 6 A handheld power tool 10 according to the present invention is shown, which is in the form of a polisher or sander. The design and function of this power tool 10 are similar to those described in prior art reference EP3012068A1, the contents of which are incorporated herein by reference for the design and function of the power tool 10. Due to its relatively small size and ability to work on confined spaces, this power tool 10 is referred to as a mini or nano polisher or sander. This power tool 10 is primarily used for localized repairs of vehicle bodies, ship and aircraft fuselages. Depending on the movement of various functional units connected to the tool shaft 18 of the power tool 10 and the resulting working elements 12 (e.g., backplate), it can be used for a variety of sanding and / or polishing operations. Because it is operated using a removable battery 14, the power tool 10 can operate independently of a main power source without the need for a cable connection.

[0034] Various types of polishing components 13 or abrasive components are detachably attached to the bottom surface of the back plate 12. For example... Figure 2b As shown, it is suggested that the bottom surface of the back plate 12 has a first layer of connectors 12a, such as the first layer of a hook-and-loop fastener (e.g., a hook); and the top surface of the polishing component 13 or the abrasive component has a second layer of connectors 13a, such as the second layer of a hook-and-loop fastener (e.g., a ring). The first and second layers of connectors 12a and 13a cooperate with each other to fix the polishing component 13 or the abrasive component to the bottom surface of the back plate 12. In addition to the hook-and-loop fastener, the layers of connectors 12a and 13a may also include adhesive surfaces or similar components.

[0035] The power tool 10 has a tool housing 16, which mainly consists of a rear portion 16a and a front portion 16b. The rear portion 16a is for the user to hold the power tool 10 by hand, and the diameter of the front portion 16b is smaller than that of the rear portion 16a. The diameter of the front portion 16b is so small that it can enter confined spaces to work on work surfaces in these spaces. An electric motor (not shown), powered by a battery 14, and possibly other electrical components are located inside the tool housing 16. The electric motor is used to drive the working element 12. The motor shaft 96 (see...) Figure 7 The tool shaft 18 of the power tool 10 can be connected via an intermediate shaft 94 and / or a gear drive 98 (e.g., a bevel gear). As described below... Figure 6 In the embodiment shown, the tool shaft 18 is located inside the front portion 16b of the tool housing 16 and can be accessed from the outside of the tool housing 16.

[0036] The power tool 10 has an actuation lever 20 located on the top side of the rear portion 16a of the tool housing 16. The actuation lever 20 is connected to an on / off switch (not shown) for turning the motor on and off. The actuation lever 20 is rotatable about a rotation axis 22, and can be activated by the user's palm holding the power tool 10 at the rear portion 16a of the tool housing 16. Alternatively, the actuation lever 20 can be located on the bottom side of the rear portion 16a of the tool housing 16, and can be activated by the user holding one or more fingers of the power tool 10 at the rear portion 16a of the tool housing 16. Optionally, the tool housing 16 may be equipped with a corresponding switch (e.g., a slide switch) instead of the actuation lever 20 for turning the motor on and off.

[0037] The power tool 10 has a rotary switch 23 located on the top side of the rear portion 16a of the tool housing 16. This rotary switch 23 is connected to a potentiometer (not shown) for increasing and / or decreasing the motor speed. The rotary switch 23 is located within a protrusion 24 on the top of the tool housing 16 and has a side opening 26 that allows the thumb and forefinger of the user holding the power tool 10 to access the rotary switch 23 from the side. Of course, the rotary switch 23 can also be located in other positions on the tool housing 16. The power tool 10 may be equipped with buttons (not shown), for example, a button marked "+" for increasing the motor speed and another button marked "-" for decreasing the motor speed, in place of the rotary switch 23.

[0038] A visual indicator 27, such as one or more LEDs, can be placed at a specific location on the tool housing 16. Figure 6In the illustrated embodiment, the visual indicator 27 is located on the top surface of the rear portion 16a of the tool housing 16, in front of the rotary switch 23, particularly on the front wall of the protrusion 24. The visual indicator 27 can indicate the operating status of one or more components of the power tool 10, such as the charging status of the battery 24. The visual indicator 27 may include one or more LEDs emitting different colors of light, such as green, yellow, and red. The visual indicator 27 may also include one or more LEDs emitting light in various light emission modes, such as continuous illumination or intermittent illumination at one or more intermittent frequencies.

[0039] The rear portion 16a of the tool housing 16 is preferably made of plastic. The front portion 16b of the housing 16 may be made of metal or plastic. Preferably, the front portion 16b of the housing 16 is made of the same plastic material as the rear portion 16a. The front portion 16b of the tool housing 16 has a tubular portion 16c that occupies most of the longitudinally extending portion of the front portion 16b of the housing 16. Preferably, an intermediate shaft 94 (see [link to relevant documentation]) is provided within the tubular portion 16c. Figure 7 The intermediate shaft connects the motor shaft 96 of the motor to the bevel gear 98 inside the front portion 16b of the tool housing 16. The bevel gear 98 converts the rotational motion of the intermediate shaft 94 about its rotation axis 28 into the rotational motion of the tool shaft 18 about its rotation axis 30. The included angle between the rotation axes 28 and 30 is α, preferably 90°≤α≤120°, and particularly α=97° or 98°.

[0040] The power tool 10 according to the invention has a quick-change working head 50 detachably connected to the front portion 16b of the tool housing. Details of the working head 50 are as follows... Figures 1 to 5 As shown, it includes an axial input adapter 52 detachably connected to the tool shaft 18 of the power tool 10, an axial output adapter 54 detachably connected to the working element 12 (e.g., backplate) of the power tool 10, and a transmission device 56 with a specific gear ratio i (see Figures 2, 4, and 5). The transmission device 56 is functionally located between the axial input adapter 52 and the axial output adapter 54 and is adapted to rotate the axial output adapter 54 at a given speed, which depends on the rotational speed of the axial input adapter 52 and the gear ratio i of the transmission device 56.

[0041] The working head 50 includes a magnetic element 58 (see...) Figure 3 The magnetic element 58 comprises one or more permanent magnets and / or one or more ferromagnetic elements. During the attachment of the working head 50 to the front portion 16b of the tool housing 16 of the handheld power tool 10, as the working head 50 approaches the front portion 16b of the tool housing 16, the magnetic element 58 is adapted to interact with a corresponding magnetic element 60 located in the front portion 16b of the tool housing 16, which comprises one or more permanent magnets and / or one or more ferromagnetic elements (see [link to relevant documentation]). Figure 6 Magnetic interaction occurs. The magnetic interaction between the magnetic element 58 of the working head 50 and the corresponding magnetic element 60 of the front portion 16b of the tool housing 16 ensures that the working head 50 is firmly fixed relative to the front portion 16b of the tool housing 16 in the axial direction parallel to the rotation axis 30 of the input adapter 52. Figures 1 to 5 In the embodiment of the working head 50 shown, when the working head 50 is connected to the front 16b of the tool housing 16 of the power tool 10, the rotation axis of the axial input adapter 52 coincides with the rotation axis 30 of the tool shaft 18 of the power tool 10.

[0042] The example working head 50 has an adapter housing 62 in which an axial input adapter 52, an axial output adapter 54, and a transmission device 56 are rotatably mounted. The adapter housing 62 of the working head 50 is axially and firmly fixed relative to the front portion 16b of the power tool 10 by magnetic interaction or magnetic force between the magnetic element 58 of the working head 50 and the corresponding magnetic element 60 of the front portion 16b of the tool housing 16. When the adapter housing 62 is firmly fixed relative to the tool housing 16 by magnetic force, it cannot rotate relative to the tool housing 16 about the rotation axis 30 of the axial input adapter 52; that is, the adapter housing 62 is fixed to the tool housing 16 in an anti-torsional manner.

[0043] The working head 50 may include a mechanical positioning device 64 (see...) Figure 3 When the working head 50 is attached to the front 16b of the tool housing 16 of the power tool 10, the mechanical positioning device 64 is adapted to engage with a corresponding mechanical positioning device 66 located in the front 16b of the tool housing 16 of the handheld power tool 10 (see...). Figure 6 Mechanical interaction occurs between the mechanical positioning device 64 of the working head 50 and the corresponding mechanical positioning device 66 of the front portion 16b of the tool housing 16, holding the working head 50 at a specific angular position relative to the front portion 16b of the tool housing 16 in the circumferential direction, which extends in a plane perpendicular to the rotation axis 30 of the axial input adapter 52. Although Figure 6 The working head 50 contains an axial input adapter 52, a magnetic element 58, and a mechanical positioning device 64, but these are not explicitly shown in the figure for clarity.

[0044] At least a portion of the mechanical positioning device 64 of the front portion 16b of the tool housing 16 of the power tool 10, and / or at least a portion of the corresponding mechanical positioning device 66 of the front portion 16b of the tool housing 16 of the power tool 10, may include one or more initial guide portions (not shown) that facilitate mechanical contact with each other. As the working head 50 moves further axially toward the front portion 16b of the tool housing 16, the initial guide portions or other portions of the mechanical positioning device 64 may guide the working head 50 relative to the front portion 16b of the tool housing 16 into an attachment position. Preferably, in this attachment position, the magnetic element 58 of the working head 50 and the corresponding magnetic element 60 of the front portion 16b of the tool housing 16 face each other and are disposed opposite each other, thereby establishing maximum magnetic force between the magnetic element 58 of the working head 50 and the corresponding magnetic element 60 of the front portion 16b of the tool housing 16. Therefore, the mechanical positioning devices 64, 66 facilitate and accelerate the attachment process of the working head 50 to the front portion 16b of the tool housing 16.

[0045] It is recommended that the mechanical positioning device 64 of the working head 50 and the corresponding mechanical positioning device 66 of the front portion 16b of the tool housing 16 have extensions that extend fully axially, parallel to the rotation axis 30 of the axial input adapter 52. Therefore, the guiding motion of the working head 50 toward the front portion 16b of the tool housing 16 to the attachment position is a strictly linear motion along the axial direction. Of course, the guiding motion can also take different forms, such as helical motion, or constitute part of the helical rotation of the working head 50 relative to the front portion 16b of the tool housing 16.

[0046] Furthermore, it is recommended that the transmission ratio i of the transmission device 56 be greater than 1, particularly preferably i > 1.5, preferably i ≥ 2, and especially preferably i = 2.36. This reduces the rotational speed and increases the torque of the axial output adapter 54 relative to the rotational speed and torque of the axial input adapter 52. This recommendation is particularly advantageous if only a small motor, especially one with a small outer diameter (typically less torque than a large motor), can be used due to space limitations within the tool housing 16. Even with such a small motor, sufficient torque can be generated on the working element 12 as long as the motor speed is high enough. For example, when the transmission ratio of the transmission device 56 is i = 2 and the maximum motor speed is approximately 5,000 rpm, the axial output adapter 54 or the backplate 12 connected to it can rotate at a maximum speed of 2,500 rpm while generating sufficient torque to polish or grind the desired working surface or workpiece, respectively.

[0047] The transmission device 56 can be designed to reduce the rotational speed of the output adapter 54 relative to the rotational speed of the input adapter 52, while changing the type or mode of motion performed by the axial output adapter 54. For example, depending on the design of the transmission device 56, the tool shaft 18 and the axial input adapter 52 can perform rotary motion, while the axial output adapter 54 can perform one of gear-driven (or forced eccentric) motion, random trajectory (or free eccentric) motion, and trajectory motion.

[0048] Of course, the transmission device can also have a transmission ratio i=1 or i<1. When i=1, the transmission device 56 is designed to keep the rotational speed of the input adapter 52 constant, while only changing the motion type of the axial output adapter 54. For example, the tool shaft 18 and the axial input adapter 52 can perform rotary motion, while the axial output adapter 54 can perform one of gear-driven (or forced eccentric) motion, random trajectory (or free eccentric) motion, and trajectory motion.

[0049] When i < 1, the transmission 56 can be designed to increase the rotational speed of the axial output adapter 54 relative to the rotational speed of the axial input adapter 52. Simultaneously, the torque generated by the output adapter 54 and the torque supplied to the backplate 12 are respectively less than the torque generated by the tool shaft 18 and the torque supplied to the input adapter 52. This is particularly advantageous for high-speed applications that do not require high torque. The transmission 56 can be designed to increase the rotational speed of the output adapter 54 relative to the rotational speed of the input adapter 52, while simultaneously changing the motion type or motion of the axial output adapter 54. For example, the tool shaft 18 and the axial input adapter 52 can perform rotary motion, while the axial output adapter 54 can perform either gear-driven (or forced eccentric) motion or random trajectory (or free eccentric) motion.

[0050] exist Figures 1 to 5 In this embodiment, the transmission device 56 is designed to convert the rotational motion of the axial input shaft 52 into the rotational motion of the axial output shaft 54, the rotational speed of which differs from that of the axial input shaft 52, wherein the rotational axes 30 of the axial input shaft 52 and the axial output shaft 54 ​​coincide. Therefore, the transmission device 56 is designed to maintain the motion type of the axial input shaft 52 and simply transmit it to the axial output shaft 54. Preferably, the rotational speed of the axial output shaft 54 ​​is less than the rotational speed of the axial input shaft 52, i.e., the transmission ratio i of the transmission device is greater than 1, and the torque provided by the axial output shaft 54 ​​and the torque provided to the back plate 12 are respectively greater than the torques provided by the tool shaft 18 of the power tool 10 and the axial input shaft 52 of the working head 50.

[0051] exist Figures 1 to 5 In one embodiment, the transmission device 56 is designed to convert the rotational motion of the axial input shaft 52 into the rotational motion of the axial output shaft 54, and the rotational direction of the axial output shaft 54 ​​is the same as that of the axial input shaft 52.

[0052] The axial input adapter 52 of the working head 50 may (not shown) include an axial groove with a non-rotationally symmetric internal cross-section, which includes a polygon, particularly a square, hexagon, or octagon. The tool shaft 18 of the power tool 10 includes a shaft-like distal end with a correspondingly non-rotationally symmetric external cross-section, which includes a polygon, particularly a square, hexagon, or octagon. The axial groove of the axial input adapter 52 of the working head 50 is adapted to receive the shaft-like distal end of the tool shaft 18 of the power tool 10 axially to establish a torque-resistant connection between the tool shaft and the axial input adapter.

[0053] Or, such as Figures 1 to 5 and Figure 7 As shown, the axial input adapter 52 of the working head 50 includes a shaft-shaped protrusion 68 having a non-rotationally symmetric outer cross-section, which includes a polygon, particularly a square, hexagon, or octagon. The tool shaft 18 of the power tool 10 includes an axial groove (see...). Figure 7 The axial groove has a corresponding non-rotationally symmetric internal cross-section, which includes polygons, particularly squares, hexagons, or octagons. The shaft-shaped protrusion element 68 of the axial input adapter 52 of the working head 50 is adapted to be inserted axially into the axial groove at the distal end of the tool shaft 18 of the power tool 10 to establish a torque-resistant connection between the tool shaft and the axial input adapter.

[0054] The connection between the shaft-shaped protrusion 68 of the axial input adapter 52 of the working head 50 and the tool shaft 18 of the power tool 10 can be performed in a manner similar to that described in prior art references EP4450221A1 (for detachably connecting an eccentric element to a tool shaft) and EP4450222A1 (for detachably connecting a polishing pad to a tool shaft). These two references are incorporated herein by reference to illustrate the detachable connection between the working head 50 (corresponding to the eccentric element in EP'221 and the polishing pad in EP'222) and the tool shaft 18. According to these references, the tool shaft has an axial groove at its distal end, defined by a hollow cylindrical sleeve, and a plurality of spherical magnetic elements are disposed on the outer wall of the hollow cylindrical sleeve of the axial groove, these magnetic elements being radially movable. When the shaft-shaped protrusion 68, made of metal (preferably steel), is inserted into the axial groove of the tool shaft 18, the spherical magnetic element is attracted by the metal material of the shaft-shaped protrusion 68 and enters the radial groove 70 provided on the outer surface of the shaft-shaped protrusion 68.

[0055] Of course, there are other possibilities for the connection between the shaft-shaped protrusion 68 of the axial input adapter 52 of the working head 50 and the tool shaft 18 of the power tool 10. These possible solutions include embodiments in which the shaft-shaped protrusion 68 is directly inserted into the axial groove of the tool shaft 18. In this case, the axial fixation of the shaft-shaped protrusion 68 in the axial groove of the tool shaft 18 is achieved by the interaction between the magnetic element 58 of the working head 50 and the corresponding magnetic element 60 of the tool housing 16.

[0056] Preferably, when the working head 50 is mounted onto the tool housing 16, the axial input adapter 52 automatically engages with the distal end of the tool spindle 18 in a torque-resistant manner. Therefore, when the adapter housing 62 of the working head 50 is securely fixed (in a torque-resistant manner) relative to the front portion 16b of the tool housing 16 by magnetic force, torque can be transmitted from the tool spindle 18 of the power tool 10 to the input adapter 52 of the working head 50. The installation and removal of the working head 50 is simple, convenient, and safe.

[0057] According to another preferred embodiment of the quick-change working head 50 of the present invention, it is suggested that the axial output adapter 54 of the working head 50 includes an axial groove 72 (see Figure 2a The axial groove has a threaded inner wall 74. Fastening pin 76 (see...) Figure 2b The fastening pin 76 is attached to the top surface 78 of the back plate 12. The distal axial end of the fastening pin 76, or the entire fastening pin 76, has a threaded outer surface 80. An axial groove 72 is used to threadedly receive the distal end of the fastening pin 76 to establish a threaded connection between the back plate 12 and the axial output adapter 54. When installing / removing the back plate 12 from the axial output adapter 54, free rotation of the output adapter 54 should be prevented. This can be achieved by a separate tool component (not shown) that can be inserted into the working head 50 to prevent free rotation of the axial output adapter 54; or by an integrated braking or locking device (not shown) that can be activated or deactivated by the user of the working head 50 or the power tool 10, respectively. This braking or locking device can be part of the working head 50.

[0058] Alternatively (not shown in the figure), the axial output adapter 54 of the working head 50 may also include a retaining pin having a axial distal end with a threaded outer surface. An axial groove with a corresponding threaded inner wall is provided on the top surface 78 of the back plate 12. The axial distal end of the retaining pin is adapted to be threadedly inserted into the axial groove of the back plate 12, thereby establishing a threaded connection between the back plate 12 and the axial output adapter 54.

[0059] like Figure 4 and Figure 5As shown, the transmission 56 may include a planetary gear configuration (or planetary gear set) consisting of multiple components. These components include a first sun gear, multiple (e.g., three) planetary gears, a ring gear, and a second sun gear. Each planetary gear set includes an upper gear and a lower gear connected to the upper gear in an anti-torque manner, the upper gear having a larger number of teeth (and a larger diameter) than the lower gear. The first sun gear meshes with the upper gear of the planetary gear set, and the second sun gear meshes with the lower gear of the planetary gear set.

[0060] exist Figure 5 In the illustrated embodiment, the adapter housing 62 is cup-shaped with an open bottom. An axial input adapter 52 or a shaft-like protrusion element 68 is inserted into the cup-shaped adapter housing 62 through a central through-hole on the closed top surface of the adapter housing 62. The first sun gear 82 (see [reference]) is supported in a torque-resistant manner at the proximal end of the input adapter 52 within the cup-shaped adapter housing 62 opposite to the shaft-like protrusion element 68. Figure 2a and Figure 7 Since the first sun gear 82 is located inside the cup-shaped adapter housing 62, therefore in Figure 5 It is not visible in the middle.

[0061] The first sun gear 82 meshes with the upper gear 84 of the planetary gear set, which transmits rotation and torque to the lower gear 86. The lower gear 86 meshes with the second sun gear 88 connected to the axial output adapter 54 in a torque-resistant manner. In addition, the lower gear 86 also meshes with the external gear ring 90 connected to the adapter housing 62. Figure 7 This was also shown in detail.

[0062] Therefore, as Figure 5 As shown, the transmission device 56 of the working head 50 includes two independent components: a first component 56', which includes a bracket 92 that rotatably holds the planetary gears 84 and 86; and a second component 56'', which includes an external gear ring 90 and a second sun gear 88 that rotatably holds the second sun gear 88. The first component 56' can be inserted into the cup-shaped adapter housing 62. After the first component 56' is inserted, the second component 56'' acts as a cover or plate to close the opening side of the cup-shaped adapter housing 62. The attachment of the second component 56'' to the first component 56'' can be achieved through threaded connection, screw connection, snap-fit ​​connection, press-fit connection, etc.

[0063] The adapter housing 62 preferably comprises two parts. The main body portion forming the structural support is indicated by reference numeral 62a. The main body portion 62a is made of rigid plastic or metal. The second part 62b, which may be attached to the front of the main body portion 62a of the adapter housing 62, is preferably made of an elastic or resilient material. It acts as a damping element to prevent damage to the work surface being processed or to other parts of the vehicle, ship, or aircraft when using the power tool 10.

Claims

1. A quick-change workhead (50) detachably attachable to the front (16b) of the tool housing (16) of a handheld power tool (10), particularly a polisher or sander, the workhead (50) comprising: An axial input adapter (52) is detachably connected to the tool spindle (18) of the power tool (10); an axial output adapter (54) is detachably connected to the working element (12) of the power tool (10), particularly the back plate; And a transmission device (56) having a specific transmission ratio (i), which is functionally located between the axial input adapter (52) and the axial output adapter (54) and is adapted to cause the axial output adapter (54) to rotate at a given speed according to the rotational speed of the axial input adapter (52) and the transmission ratio (i) of the transmission device (56). Its characteristics are: The working head (50) includes a magnetic element (58) comprising one or more permanent magnets and / or one or more ferromagnetic elements. During the attachment of the working head (50) to the front portion (16b) of the tool housing (16) of the handheld power tool (10), as the working head (50) approaches the front portion (16b) of the tool housing (16), the magnetic element (58) is adapted to magnetically interact with a corresponding magnetic element (60) located in the front portion (16b) of the tool housing (16) of the handheld power tool (10), which comprises one or more permanent magnets and / or one or more ferromagnetic elements. The magnetic interaction between the magnetic element (58) of the working head (50) and the corresponding magnetic element (60) of the front portion (16b) of the tool housing (16) ensures that the working head (50) is securely fixed axially relative to the front portion (16b) of the tool housing (16), the axial direction extending parallel to the rotation axis (30) of the axial input adapter (52).

2. The quick-change working head (50) according to claim 1, wherein, The working head (50) includes a mechanical positioning device (64) which, when the working head (50) is attached to the front (16b) of the tool housing (16) of the power tool (10), is adapted to mechanically interact with a corresponding mechanical positioning device (66) located in the front (16b) of the tool housing (16) of the handheld power tool (10), wherein the mechanical interaction between the mechanical positioning device (64) of the working head (50) and the corresponding mechanical positioning device (66) of the front (16b) of the tool housing (16) holds the working head (50) at a specific angular position relative to the front (16b) of the tool housing (16) in a circumferential direction that extends in a plane perpendicular to the rotation axis (30) of the axial input adapter (54).

3. The quick-change working head (50) according to claim 2, wherein, The mechanical positioning device (64) of the working head (50) has an extension that extends fully axially and parallel to the rotation axis (30) of the axial input adapter (52).

4. The quick-change working head (50) according to any of the preceding claims, wherein the transmission ratio (i) of the transmission device (56) is i>1, especially i>1.5, particularly preferably i≥2, especially i=2.36, thereby reducing the speed of the axial output adapter (54) and increasing the torque relative to the speed and torque of the axial input adapter (52).

5. The quick-change working head (50) according to any one of claims 1 to 3, wherein, The transmission device (56) is designed to convert the rotational motion of the axial input shaft (52) into the rotational motion of the axial output shaft (54), and the rotational speed of the axial output shaft (54) is different from that of the axial input shaft (52). The rotational axes (30) of the axial input shaft (52) and the axial output shaft (54) coincide with each other.

6. The quick-change working head (50) according to claim 5, wherein the transmission device (56) is designed to convert the rotational motion of the axial input shaft (52) into the rotational motion of the axial output shaft (54) having the same rotational direction as the axial input shaft (52).

7. The quick-change working head (50) according to any one of claims 1 to 3, wherein, The axial input adapter (52) of the working head (50) includes an axial groove having a non-rotationally symmetric internal cross-section, including polygons, particularly squares, hexagons or octagons, and is adapted to receive the axial distal end of the tool shaft (18) of the power tool (10) in the axial direction to establish a torque-resistant connection between the tool shaft (18) and the axial input adapter (52).

8. The quick-change working head (50) according to any one of claims 1 to 3, wherein, The axial input adapter (52) of the working head (50) includes a shaft-shaped protrusion (68) having a non-rotationally symmetric external cross-section comprising a polygon, particularly a square, hexagon, or octagon, and adapted to be inserted axially into an axial groove at the distal end of the tool shaft (18) of the power tool (10) to establish a torque-resistant connection between the tool shaft (18) and the axial input adapter (52).

9. The quick-change working head (50) according to any one of claims 1 to 3, wherein, The axial output adapter (54) of the working head (50) includes an axial groove (72) having a threaded inner wall (74) adapted to receive the axial distal end of a fastening pin (76) in a threaded manner to establish a threaded connection between the back plate (12) and the axial output adapter (54), the fastening pin (76) being attached to the top surface (78) of the back plate (12) and having a threaded outer surface (80).

10. The quick-change working head (50) according to any one of claims 1 to 3, wherein, The axial output adapter (54) of the working head (50) includes a fastening pin having a threaded outer surface adapted to be threadedly inserted into an axial groove provided on the top surface (78) of the back plate (12) having a threaded inner wall to establish a threaded connection between the back plate (12) and the axial output adapter (54).

11. The quick-change working head (50) according to any one of claims 1 to 3, wherein, The working head (50) has an adapter housing (62) in which an axial input adapter (52), an axial output adapter (54), and a transmission device (56) are rotatably mounted. The axial input adapter (52) is adapted to rotate about the rotation axis (30), and The magnetic element (58) is part of the adapter housing (62) of the working head (50) or attached to the adapter housing (62) of the working head (50), but the magnetic element (58) is not part of the axial input adapter (52) of the working head (50).

12. A handheld power tool (10), particularly a polisher or sander, having a tool housing (16) and a quick-change head (50) detachably attached to the front (16b) of the tool housing (16) of the power tool (10), the head (50) comprising an axial input adapter (52) detachably connected to the tool shaft (18) of the power tool (10); an axial output adapter (54) detachably connected to the working element (12) of the power tool (10), particularly a backplate; and a transmission (56) having a specific gear ratio (i), the transmission (56) functionally located between the axial input adapter (52) and the axial output adapter (54), and adapted to cause the axial output adapter (54) to rotate at a given speed according to the rotational speed of the axial input adapter (52) and the gear ratio (i) of the transmission (56), Its characteristics are: The working head (50) includes a magnetic element (58) comprising one or more permanent magnets and / or one or more ferromagnetic elements. The front portion (16b) of the tool housing (16) of the handheld power tool (10) includes a corresponding magnetic element (60) comprising one or more permanent magnets and / or one or more ferromagnetic elements. During attachment of the working head (50) to the front portion (16b) of the tool housing (16) of the handheld power tool (10), as the working head (50) approaches the front portion (16b) of the tool housing (16), the magnetic element (58) is adapted to magnetically interact with the corresponding magnetic element (60), wherein... The magnetic interaction between the magnetic element (58) of the working head (50) and the corresponding magnetic element (60) of the front part (16b) of the tool housing (16) ensures that the working head (50) is firmly fixed in the axial direction relative to the front part (16b) of the tool housing (16), which extends parallel to the rotation axis (30) of the axial input adapter (52).

13. The handheld power tool (10) according to claim 12, wherein, The working head (50) includes a mechanical positioning device (64) which, when the working head (50) is connected to the front (16b) of the tool housing (16) of the power tool (10), is adapted to mechanically interact with a corresponding mechanical positioning device (66) located in the front (16b) of the tool housing (16) of the handheld power tool (10), wherein the mechanical interaction between the mechanical positioning device (64) of the working head (50) and the corresponding mechanical positioning device (66) in the front (16b) of the tool housing (16) holds the working head (50) at a specific angular position relative to the front (16b) of the tool housing (16) in a circumferential direction that extends in a plane perpendicular to the rotation axis (30) of the axial input adapter (54).

14. The handheld power tool (10) according to claim 13, wherein, The mechanical positioning device (64) of the working head (50) and the corresponding mechanical positioning device (66) of the front part (16b) of the tool housing (16) have extensions that extend fully axially, which extend parallel to the rotation axis (30) of the axial input adapter (52).

15. The handheld power tool (10) according to any one of claims 12 to 14, wherein, The axial input adapter (52) of the working head (50) includes an axial groove having a non-rotationally symmetric internal cross-section, including polygons, particularly squares, hexagons, or octagons; the tool spindle (18) of the power tool (10) includes a shaft-like distal end having a corresponding non-rotationally symmetric external cross-section, including polygons, particularly squares, hexagons, or octagons; the axial groove of the axial input adapter (52) of the working head (50) is adapted to receive the shaft-like distal end of the tool spindle (18) in the axial direction to establish a torque-resistant connection between the tool spindle (18) and the axial input adapter (52).

16. The handheld power tool (10) according to any one of claims 12 to 14, wherein, The axial input adapter (52) of the working head (50) includes a shaft-shaped protrusion (68) having a non-rotationally symmetric external cross-section comprising a polygon, particularly a square, hexagon, or octagon; the distal end of the tool spindle (18) of the power tool (10) includes an axial groove having a non-rotationally symmetric internal cross-section comprising a polygon, particularly a square, hexagon, or octagon; the shaft-shaped protrusion (68) of the axial input adapter (52) is adapted to be axially inserted into the axial groove at the distal end of the tool spindle (18) to establish a torque-resistant connection between the tool spindle (18) and the axial input adapter (52).

17. The handheld power tool (10) according to any one of claims 12 to 14, wherein, The handheld power tool (10) includes a working head (50) according to any one of claims 1 to 3.

18. The handheld power tool (10) according to any one of claims 12 to 14, wherein, The handheld power tool (10) includes a working head (50) according to claim 11.

Images