EP3132892B1

EP3132892B1 - Multi-sander kit

Info

Publication number: EP3132892B1
Application number: EP16184802.3A
Authority: EP
Inventors: Tsz Kin Wong
Original assignee: Techtronic Power Tools Technology Ltd
Current assignee: Techtronic Power Tools Technology Ltd
Priority date: 2015-08-20
Filing date: 2016-08-18
Publication date: 2020-11-18
Anticipated expiration: 2036-08-18
Also published as: EP3132892A2; EP3132892A3; CN106466798A

Description

FIELD OF INVENTION

This invention relates to electronic power tools, and in particular to power tools used to smooth surfaces by abrasion.

BACKGROUND OF INVENTION

Sanders are used commonly in various applications such as indoor decorations and material processing to smooth surfaces by abrasion with sandpaper. Sanders have a means to attach the sandpaper, for example a sanding pad to which the sandpaper can be adhered or otherwise secured, and a mechanism to move the sandpaper rapidly contained within a housing. There are many different types of electronically powered sanders for different purposes. For example, an orbital sander is used where the sandpaper delivers a random-orbit action for fine sanding or where little material needs to be removed. On the other hands, drywall sanders are used on the drywall and are usually designed with a particular emphasis on dust control to prevent generating a lot of dusts which contaminate the environment.
However, conventionally sanders made for different purposes are designed and sold separately. For example, existing orbital sanders and drywall sanders are two kinds of products on the market where the user has to purchase both units. The orbital sanders and drywall sanders cannot be used interchangeably. This is because conventional orbital sanders are not suitable to be used on drywall sanding where the drywall dust will damage the sander and the dust will spread around to the environment easily which can cause harm to the user's health.

SUMMARY OF INVENTION

In the light of the foregoing background, it is an object of the present invention to provide an alternative sander which eliminates or at least alleviates the above technical problems.
The above object is met by the combination of features of the main claim; the subclaims disclose further advantageous embodiments of the invention.
One skilled in the art will derive from the following description other objects of the invention. Therefore, the foregoing statements of object are not exhaustive and serve merely to illustrate some of the many objects of the present invention.
Accordingly, the present invention, in one aspect, is a multi-sander kit containing a multi-sander and a sander attachment. The multi-sander contains a casing, an electric motor located in the casing, and a driving shaft driven by the electric motor and protruding out of the casing. An end of the driving shaft is adapted to allow a sanding pad to connect thereto. The casing further contains an interface adjacent to the end of the driving shaft. The sander attachment is adapted to be detachably installed to the multi-sander by connecting the sander attachment to the interface. The sander attachment covers at least partially the driving shaft or the sanding pad when the sander attachment and the sanding pad are installed to the multi-sander.
Preferably, the casing further includes a cylindrical portion adjacent to the end of the driving shaft; the interface configured on a circumferential face of the cylindrical portion.
More preferably, the sander attachment is chosen from the group consisted of a random orbital (RO) attachment and a drywall attachment.
In one variation, the RO attachment is formed to cover only a part of the sanding pad when the sander attachment and the sanding pad are installed to the multi-sander.
EP-A-1674202 , which is the basis for the preamble of appended claim 1, describes a modular sander-casing architecture. EP-A-2479000 describes a dust-collecting cover for disc grinder. JP-A-2012115947 describes a grinding tool. US-A-2009/209184 describes a hand-held power tool for a rotating tool with guard. US-A-2009/215365 describes a sanding tool with pivotally coupled head assembly.
The RO attachment includes a first segment having a substantially arc shape; and a second segment having a substantially arc shape. The first segment and the second segment are adapted to be connected to each other in a head-to-tail manner, so as to circumferentially enclosing at least a part of the sanding pad when the sander attachment and the sanding pad are installed to the multi-sander.
The first segment and the second segment each has a first end and a second end; the first end of the first segment capable of connecting to the first end of the second segment. The second end of the first segment is capable of connecting to the second end of the second segment.
The first end of the first segment is capable of connecting to the first end of the second segment via a pin-knuckle structure.
The second end of the first segment is capable of connecting to the second end of the second segment via a latch.
The interface is first geometric patterns formed on the circumferential face of the cylindrical portion. The first segment and the second segment contain second geometric patterns complementing the first geometric patterns whereby the first segment and the second segment are adapted to connect to the interface.
Preferably, the first and second geometric patterns contain grooves and protrusions extending along a circumferential direction.
More preferably, the second geometric patterns comprise at least one protrusion extending inwardly to the center of the sanding pad.
Most preferably, the second geometric patterns contain a plurality of protrusions, which extend inwardly to different extents, or which have different spans along the circumferential direction.
In one variation, one of the protrusions is placed between a lower part of the casing and the sanding pad when the sander attachment and the sanding pad are installed to the multi-sander.
According to another variation, the drywall attachment is formed to fully cover the sanding pad on a circumferential direction when the sander attachment and the sanding pad are installed to the multi-sander.
Preferably, the drywall attachment further contains a rim of brush which fully covers the sanding pad on the circumferential direction.
More preferably, the rim of brush has a larger dimension compared to the sanding pad along the axial direction of the driving shaft.
In one implementation, the rim of brush contains nylon strip brushes.
The drywall attachment includes a first segment having a substantially arc shape, a second segment having a substantially arc shape; and a third segment having a substantially arc shape. The first segment, the second segment and the third segment are adapted to be connected to each other in a head-to-tail manner, so as to fully cover the sanding pad on a circumferential direction when the sander attachment and the sanding pad are installed to the multi-sander.
At least two of the first segment, the second segment and the third segment are connected to each other via a pin-knuckle structure or a hook-tab structure.
The interface is first geometric patterns formed on the circumferential face of the cylindrical portion. The first segment, the second segment and the third segment contain second geometric patterns complementing the first geometric patterns whereby the first segment, the second segment and the third segment are adapted to connect to the interface.
Preferably, the first and second geometric patterns contain grooves and protrusions extending along a circumferential direction.
More preferably, the second geometric patterns contain at least one protrusion extending inwardly to the center of the sanding pad.
Most preferably, the second geometric patterns contain a plurality of protrusions, which extend inwardly to different extents, or which have different spans along the circumferential direction.
In one variation, the sanding pad has a substantial truncated cone shape.
In another variation, the sanding pad has a polygonal cross-sectional shape.
Preferably, the sanding pad has a rectangular cross-sectional shape.
There are many advantages to the present invention, as one of the most apparent advantages is that the multi-sander provided in the present invention enables a single sander unit to be used with more than one optional accessory. The interchangeable design of the multi-sander allows the user to change their sander from an orbital sander to a drywall sander or reverse by replacing / attaching / removing the bottom parts. In "orbital sander mode", the sander can be used as a normal sander for sanding wood surface, etc. In "drywall sander mode", there is strip brush surrounding the sanding pad which can help to prevent dust from spreading out to the environment. Such a design is particularly suitable for working on drywall with the sander connected to a suction source, e.g. a vacuum source.
Another advantage of the present invention is that the user's expense involved in obtaining the sander for multiple purposes can be reduced. A user does not have to buy two separate sander units for different purposes such as drywall sanding and orbital sanding. Rather, the user could according to his requirement purchase the random orbital attachment, the drywall attachment, or both, for installing to the same multi-sander unit. Other types of attachments beside the random orbital attachment and the drywall attachment may also be designed to be used in the multi-sander. From the user's point of view, they do not need to buy a dedicated drywall sander for drywall work. In addition, by configuring a single sander unit with multiple, optional attachments, it is easier for storing and transporting the sander as the weight and occupying space of the sander kit in the present invention is apparently less than that of two separate sander units.

BRIEF DESCRIPTION OF FIGURES

The foregoing and further features of the present invention will be apparent from the following description of preferred embodiments which are provided by way of example only in connection with the accompanying figures, of which:

Fig. 1 is a perspective view of a multi-sander according to one embodiment of the present invention, without any attachment installed.
Fig. 2 is the perspective view of the multi-sander in Fig. 1 from another angle of view.
Fig. 3 is the perspective view of the multi-sander in Fig. 1 from a further angle of view, where the sanding pad is detached from the sander.
Fig. 4 is a perspective view of the multi-sander in Fig. 1 with a random orbital attachment installed according to one embodiment of the present invention.
Fig. 5 is the perspective view of the multi-sander with the random orbital attachment in Fig. 4 from another angle of view.
Fig. 6 shows the multi-sander in Fig. 4 where the random orbital attachment is dissembled and detached from the sander.
Fig. 7 is a cross-sectional view of the multi-sander with the random orbital attachment in Fig. 4.
Figs. 8a-8d illustrate the steps of installing the random orbital attachment shown in Figs. 4-7 to the multi-sander.
Fig. 9 is a perspective view of the multi-sander in Fig. 1 with a drywall attachment installed according to one embodiment of the present invention.
Fig. 10 is the perspective view of the multi-sander with the drywall attachment in Fig. 9 from another angle of view.
Fig. 11 shows the multi-sander in Fig. 9 where the drywall attachment is dissembled and detached from the sander.
Fig. 12 is a cross-sectional view of the multi-sander with the drywall attachment in Fig. 9.
Figs. 13a-13f illustrate the steps of installing the drywall attachment shown in Figs. 9-12 to the multi-sander.

In the drawings, like numerals indicate like parts throughout the several embodiments described herein.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Terms such as "horizontal", "vertical", "upwards", "downwards", "above", "below" and similar terms as used herein are for the purpose of describing the invention in its normal in-use orientation and are not intended to limit the invention to any particular orientation, the scope of the invention being defined by the appended claims.
Referring now to Figs. 1-2, an embodiment of the present invention is a multi-sander which is capable of installing various attachments (not shown) to achieve different functions. The multi-sander 20 includes a casing which is consisted of an upper part 24, a middle part 32 and a lower part 26. The upper part 24 has a substantial water droplet shape, and is suitable for a user to hold it in order to manipulate the multi-sander 20. The middle part 32 and lower part 26 both have round shape cross-sections in the horizontal planes, with the middle part 32 connecting the upper part 24 and the lower part 26 together. At the bottom end of the lower part 26, there is removably connected a sanding pad 34 which has a truncated cone shape. The sanding pad 34 is used to attach a sandpaper (not shown) for the sanding operation. There is an electric motor (not shown) located in the casing, and in particular accommodated within the interior space of the middle part 32 and the lower part 26. There is also a driving shaft (not shown) driven by the electric motor and protruding out of the casing for connecting the sanding pad 34 to an end of the driving shaft. The lower part 26 of the casing is also configured with an exhaust port 38 which is adapted to be connected to an adapter 30. The other end of the adapter 30 away from the exhaust port 38 is adapted to be connected to an external suction source, for example a vacuum source, so as to suction the dust generated during the sanding operation, as those skilled in the art would understand.
In addition, the casing of the multi-sander 20 further contains an interface on the lower part 26 and adjacent to the end of the driving shaft to which the sanding pad 34 is connected. The interface is used for connecting various sanding attachments (which will be described by examples in details below) to the multi-sander 20 to perform different task. As shown in Fig. 2 and Fig. 3, the interface contains at least a groove 42 configured on a rim portion 36 of the lower part 26 and extending along the circumferential direction, and a stop face 40 which forms an angle with the rim portion 36. There is also a generally circular protruding rim 48 formed on the lower part 26. The groove 42, the rim portion 36, the stop face 40 and the protruding rim 48 are part of the first geometric patterns which form the interface on the sander casing.
In Fig. 3, the sanding pad 44 is shown to be removed from the multi-sander 20, as the sanding pad 44 is adapted to be mounted to the sander 20 via screw connections. There are four through holes 46 formed symmetrically around the center on the sanding pad 44. Correspondingly, at the bottom of the sander 20 there is a pad socket 50 which is drivably connected to the driving shaft of the sander 20. There are also four through holes 51 formed on the pad socket 50 so that when the through holes 51 and 46 are aligned, the sanding pad 34 can be secured to the pad socket 50 by using screws (not shown) passing through the through holes 51 and 46. Also, on the sanding pad 34 but radially outer than the through holes 46 are dust extraction holes 44 through which dusts generated during sanding operation can pass through with air stream generated by the suction source.
Figs. 4-5 show the multi-sander described above with a random orbit (RO) attachment installed to the sander. The sanding pad 34 is also installed in the illustrated sander. The RO attachment includes a first segment 52, and a second segment 54. The first segment 52 and the second segment 54 are in substantial arc shapes, and are configured in head-to-tail manner that is every end of the first segment 52 is connected to an end of the second segment 54 so that the first segment 52 and the second segment 54 adjoin each other along the circumferential direction. The first segment 52 and the second segment 54 together form a complete loop. There is also a latch connecting one end of the first segment 52 and one end of the second segment 54. As shown in the figures, the RO attachment fully covers the sanding pad 34 on a circumferential direction, but only partially covers the sanding pad 34 along the vertical direction. In particular, a skirt 58 consisted of two separate pieces extending respectively from the first segment 52 and the second segment 54 is arranged to cover only a part of the sanding pad 34 along the vertical direction (that is the axial direction of the driving shaft of the sander).
Turning to Fig. 6, the RO attachment in its disassembled state and removed from the sander 20 is shown to expose the sanding pad 34 installed on the sander 20. Each of the first segment 52 and the second segment 54 is in a half-circle shape, which together form a complete loop. On the first segment 52, there is a stop face 60 which complements the stop face 40 on the sander 20. On both the first segment 52 and the second segment 54, there are formed first protrusions 71, second protrusions 72, and third protrusions 66, all of which extend inwardly along the radial direction of the first segment 52 and the second segment 54. However, the spans of the first protrusions 71, the second protrusions 72, and the third protrusions 66 along the circumferential direction are not the same. The first protrusions 71 complement the groove 42 on the sander casing described previously, and have the smallest spans along the circumferential direction. The second protrusions 72 are adapted to be inserted between the protruding rim 48 (not shown, but see Fig. 3) and another circular surface on the sander casing. The second protrusions 72 have a larger span along the circumferential direction when compared to the first protrusions 71. The third protrusions 66 are adapted to be inserted into the space between the lower part of the sander 20 and the sanding pad 34. The second protrusions 72 actually form a complete loop and so are the third protrusions 66. The first protrusions 71, the second protrusions 72, and the third protrusions 66 are part of the second geometric patterns which are designed to complement the first geometric patterns described above to connect the RO attachment including the first segment 52 and the second segment 54 to the interface of the sander casing.
The first segment 52 and the second segment 54 each have a first end and a second end as shown in Fig. 6. On a first end of the first segment 52, there is formed a knuckle (not shown) which is configured to receive a pin 68 formed on a first end of the second segment 54 so as to pivotally connect the first ends of the segment 52 and the second segment 54. On the other end, the latch 56 described above contains a hook 62 pivotally connected to a second end of the first segment 52, and a recessed face 64 formed on a second end of the second segment 54 which is adapted to hold the hook 62 and thus close the latch 56.
Fig. 7 shows the internal structure of the sander described above with the sanding pad 34 and the RO attachment installed. One can see that the motor 76 is connected to a driving shaft 74 where the end of the driving shaft 74 drivably connects to the sanding pad 34. The first segment and the second segment of the RO attachment on one end are connected by the pin 68 and knuckle 70, and on another end are connected by the latch 56. On each of the first segment and the second segment there are formed the three parallel first protrusions 71, second protrusions 72, and third protrusions 66. They match with the corresponding complementing shape of the interface on the sander casing as described above to firmly but detachably secure the RO attachment to the sander casing. The RO attachment also contains a skirt 58 which only partially covers the sanding pad 34 on the vertical direction.
Now turning to the installation of the RO attachment of the device described above, Figs. 8a-8d show how the sander according to the present invention may be installed with a RO attachment by the user without using any external tools. Start with a multi-sander 20 with only a sanding pad 34 installed, as shown in Fig. 8a the user firstly connects the first segment 52 of the RO attachment by aligning it and pushing it along the direction of the arrow 78 toward the lower part of the sander casing. In this process the above mentioned grooves and protrusions on the first segment 52 fit to their respective counterpart on the interface of the sander 20 so that the first segment 52 is installed precisely in the intended location. Next, as shown in Fig. 8b the user connects first ends of the first segment 52 and the second segment 54 together by moving the second segment 54 along the direction shown by arrow 80 toward the sander casing, and inserting the pin 68 downwardly along the direction shown by arrow 69 into the first end of the first segment 52 into the knuckle 70 on the first end of the second segment 54. The second segment 54 is then connected to the first segment 52 at one point and able to pivot with respect to the pin 68. Next, the user as shown in Fig. 8c closes the second segment 54 by rotating around the pin-knuckle structure above so that the second segment 54 moves in a rotating direction indicated by arrow 82 and finally close fully fit on the lower part of the sander casing, where the first segment 52 and the second segment 54 together form a complete loop. Note that like the case of first segment 52, the second geometric patterns on the second segment 54 also complement the first geometric patterns on the interface on the sander casing as described above to firmly but detachably secure the RO attachment to the sander casing. Lastly, as shown in Fig. 8d the user closes the latch 56 along the direction indicated by the arrow 84 to securely connect the second ends of the first segment 52 and the second segment 54 together, thus completing the installation of the RO attachment to the sander.
Figs. 9-10 show the multi-sander described above with a drywall attachment installed to the sander. The sanding pad 34 is also installed in the illustrated sander. The drywall attachment includes a first segment 152, a second segment 154, and a third segment 153. The first segment 152, the second segment 154 and the third segment 153 are configured in head-to-tail manner so that the first segment 152, the second segment 154 and the third segment 153 adjoin each other along the circumferential direction. The first segment 152, the second segment 154 and the third segment 153 together form a complete loop. Note that however first segment 152, the second segment 154 themselves would be able to close the loop since they are adapted to be connected to each other on both ends, but the structure formed by only first segment 152 and second segment 154 contains a recess part which is to be complemented by the third segment 153 to form a complete circular shape.
There are two types of connections between the adjacent ends of every two of the first segment 152, the second segment 154 and the third segment 153. The first type of connection is the pin-knuckle connection consisted of a pin 168 and a knuckle 170 similar to the pin-knuckle described previously. The second type of the connection is a hook-tab structure 157, which will be described in more details later. As shown in the figures, the drywall attachment not only fully covers the sanding pad 34 on a circumferential direction, but also fully covers the sanding pad 34 along the vertical direction by configuring a rim of brush 186. The rim of brush 186 extends at least the same distance along the vertical direction compared to the sanding pad 34 and when the sander 20 is placed on a flat work surface the rim of brush 186 directly contacts the work surface.
Turning to Fig. 11, the drywall attachment in its disassembled state and removed from the sander 20 is shown to expose the sanding pad 34 installed on the sander 20. Each of the first segment 152 and the second segment 154 is in a half-circle shape. As mentioned above although the first segment 152 and the second segment 154 themselves could form a complete loop, there is a recess part on the structure formed as such and the third segment 153 must be installed to form a complete structure. In particular, only installing the first segment 152 and the second segment 154 results in a rim of brush present for a part of the circumferential direction, and only with the third segment 153 the full circle of rim of brush would be made. On the third segment 153, there is a stop face 160 which complements the stop face 40 on the sander 20. On both the first segment 52 and the second segment 54, there are formed second protrusions 172. On the third segment 153, there is formed a first protrusion 171 as well as the second protrusion 172. Both the first protrusion 171 and the second protrusions 172 extend inwardly along the radial direction of the first segment 152, the third segment 153, and the second segment 154. However, the spans of the first protrusion 171 and the second protrusions 172 along the circumferential direction are not the same. The first protrusion 171 on the third segment 153 complements the groove 42 on the sander casing described previously, and has the smaller spans along the circumferential direction. The second protrusions 172 are adapted to be inserted between the protruding rim 48 (not shown, but see Fig. 3) and another circular surface on the sander casing. The second protrusions 172 have a larger span along the circumferential direction when compared to the first protrusion 171. The second protrusions 172 actually form a complete loop. The first protrusion 171 and the second protrusions 172 are part of the second geometric patterns which are designed to complement the first geometric patterns described above to connect the drywall attachment including the first segment 152 and the second segment 154 to the interface of the sander casing.
The first segment 152, the second segment 154 and the third segment 153 each has a first end and a second end as shown in Fig. 11. They are also in substantial arc shapes. On a first end of the first segment 152, there is formed a knuckle (not shown) which is configured to receive a pin 168 formed on a first end of the second segment 154 so as to pivotally connect the first ends of the segment 152 and the second segment 154. On the other end, the latch 156 described above contains a hook 162 pivotally connected to a second end of the first segment 152, and a recessed face 164 formed on a second end of the second segment 154 which is adapted to hold the hook 162 and thus close the latch 156. In this way, the first segment 152 and the second segment 154 can be connected in a head-and-tail manner. In addition, the third segment 153 features hook-tab structures for connecting to both the first segment 152 and the second segment 154. On the two ends of the third segment 153, there are formed tabs 161 which contain small perforations. On the first segment 152 and the second segment 154 there are also formed corresponding hooks 159 for engaging the tabs 161. Note that the hooks 159 are not located on the second ends of the first segment 152 and the second segment 154 as mentioned above, but rather they are placed at a predetermined distance away from the second end of the first segment 152 or the second segment 154 so that the circumferential span between the hooks 159 is made to be able to accommodate the third segment 153.
Fig. 12 shows the internal structure of the sander described above with the sanding pad 34 and the drywall attachment installed. One can see that the motor 76 is connected to a driving shaft 74 where the end of the driving shaft 74 drivably connects to the sanding pad 34. The first segment and the second segment of the drywall attachment on one end are connected by the pin 168 and knuckle 170, and on another end are connected by the latch 156. On each of the first segment and the second segment there is formed the second protrusions 172. Additionally on the third segment 153 there is formed a first protrusion 171. The first protrusion 171 and the second protrusions 172 match with the corresponding complementing shape of the interface on the sander casing as described above to firmly but detachably secure the drywall attachment to the sander casing. Since on each one of the first segment 152, the second segment 154 and the third segment 153 there are connected a rim of brush, the three segments together provide a full circle of rim of brush to prevent dust from going out of the sanding operation region. The rim of brush is preferably nylon strip brushes.
Now turning to the installation of the drywall attachment of the device described above, Figs. 13a-13d show how the sander according to the present invention may be installed with a drywall attachment by the user without using any external tools. Start with a multi-sander 20 with only a sanding pad 34 installed, as shown in Fig. 13a the user firstly connects the first segment 152 of the RO attachment by aligning it and pushing it along the direction of the arrow 178 toward the lower part of the sander casing. In this process the above mentioned grooves and protrusions on the first segment 152 fit to their respective counterpart on the interface of the sander 20 so that the first segment 152 is installed precisely in the intended location. Next, as shown in Fig. 13b the user connects first ends of the first segment 152 and the second segment 154 together by moving the second segment 154 along the direction shown by arrow 180 toward the sander casing, and inserting the pin 168 downwardly along the direction shown by arrow 169 into the first end of the first segment 152 into the knuckle 170 on the first end of the second segment 154. The second segment 154 is then connected to the first segment 152 at one point and able to pivot with respect to the pin 168. Next, the user as shown in Fig. 13c closes the second segment 154 by rotating around the pin-knuckle structure above so that the second segment 154 moves in a rotating direction indicated by arrow 182 and finally close fully fit on the lower part of the sander casing. The user then closes the latch 156 by moving it along the direction indicated by arrow 184 to securely connect the second ends of the first segment 152 and the second segment 154 together. Note that like the case of first segment 152, the second geometric patterns on the second segment 154 also complement the first geometric patterns on the interface on the sander casing as described above to firmly but detachably secure the drywall attachment to the sander casing. As shown in Fig. 13d, the user then installs the third segment 153 to the sander casing by fitting it to the lower part of the sander casing along the direction indicated by the arrow 163. In this process, one end of the third segment 153 is secured to the first segment 152 by locking the tab 161 on this end to the hook 159 on the first segment 152. The user in the next step shown in Fig. 13e secures the other end of the third segment 153 in a similar manner by locking the tab 161 to the hook 159 on the second segment 154. Finally, the installation of the drywall attachment is complete as shown in Fig. 13f.
The exemplary embodiments of the present invention are thus fully described. Although the description referred to particular embodiments, it will be clear to one skilled in the art that the present invention may be practiced with variation of these specific details. Hence this invention, the scope of which is defined by the appended claims, should not be construed as limited to the embodiments set forth herein.
While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only exemplary embodiments have been shown and described and do not limit the scope of the invention, which is defined by the appended claims.
For example, although the sanding pad shown above has a circular cross-sectional shape, this should not be construed as a limitation to the present invention. One skilled art should realize that other shapes of sanding pad, for example a triangular one or a rectangular one as commonly seen in the field, can also be used together with the sander attachment provided by the present invention.
Also, although the specific geometric patterns are illustrated in preferred embodiments for aligning and securing the sander attachments to the interface of the sander casing lower part, one should understand that there can be other types of structures for installing the sander attachments. The important idea about the present invention is the detachable design of a sander attachment to perform different tasks on a same sander unit, and the way of installing the attachment, including the number of segments the attachment has, can be varied according to different requirement for different applications.

Claims

A multi-sander kit, comprising:
a multi-sander (20) comprising a casing, an electric motor located in said casing, and a driving shaft driven by said electric motor and protruding out of said casing; an end of said driving shaft adapted to allow a sanding pad (34) to connect thereto; wherein said casing further comprises an interface adjacent to said end of said driving shaft wherein the casing further comprises a cylindrical portion adjacent to the end of the driving shaft, the interface being first geometric patterns formed on a circumferential face of the cylindrical portion;

the multi-sander kit further comprising a sander attachment, wherein the multi-sander is adapted to be detachably connected with said sander attachment at said interface, the multi-sander kit being characterized in that said sander attachment is chosen from a group of sander attachments comprising a random orbital (RO) attachment and a drywall attachment for carrying out random orbital (RO) sanding and drywall sanding respectively;

wherein the RO attachment comprises:
a) a first segment (52, 152) having a substantially arc shape; and

b a second segment (54, 154) having a substantially arc shape;

wherein the first segment and the second segment are adapted to connect to each other in a head-to-tail manner, so as to circumferentially enclose at least a part of the sanding pad (34) when the sander attachment and the sanding pad are installed to the multi-sander (20),

and wherein the first segment (52, 152) and the second segment (54, 154) each has a first end and a second end; the first end of the first segment capable of connecting to said first end of the second segment; the second end of the first segment capable of connecting to the second end of the second segment; and wherein the first end of the first segment is capable of connecting to the first end of the second segment via a pin-knuckle structure; and wherein the second end of the first segment is capable of connecting to the second end of the second segment via a latch (56);

and wherein the first segment (52, 152) and the second segment (54, 154) comprise second geometric patterns complementing the first geometric patterns whereby the first segment and the second segment are adapted to connect to the interface; and

wherein the drywall attachment comprises:
a) a first segment (52, 152) having a substantially arc shape;

b) a second segment (52, 152) having a substantially arc shape; and

c) a third segment (153) having a substantially arc shape;

wherein the first segment, the second segment and the third segment are adapted to connect to each other in a head-to-tail manner, so as to fully cover the sanding pad (34) on a circumferential direction when the sander attachment and the sanding pad are installed to the multi-sander (20), wherein at least two of the first segment, the second segment and the third segment are connected to each other via a pin-knuckle structure or a hook-tab structure, and

wherein the first segment (52, 152), the second segment (54, 154) and the third segment (153) comprise second geometric patterns complementing the first geometric patterns whereby the first segment, the second segment and the third segment are adapted to connect to the interface, and

wherein the first and second geometric patterns comprise grooves (42) and protrusions (71, 72, 66, 171, 172) extending along a circumferential direction.
The multi-sander kit of claim 1, wherein the second geometric patterns comprise at least one protrusion (71, 72, 66, 171, 172) extending inwardly to the center of the sanding pad (34).
The multi-sander kit of claim 1 or 2, wherein the second geometric patterns comprise a plurality of protrusions (71, 72, 66, 171, 172), which extend inwardly to different extents, or which have different spans along the circumferential direction.
The multi-sander kit of any one of claims 1 to 3, wherein one of the protrusions is placed between a lower part (26) of the casing and the sanding pad when the sander attachment and the sanding pad are installed to the multi-sander (20).
The multi-sander kit of claim 1, wherein the drywall attachment is formed to fully cover the sanding pad (34) on a circumferential direction when the sander attachment and the sanding pad are installed to the multi-sander (20).
The multi-sander kit of claim 1 or claim 5, wherein the drywall attachment further comprises a rim of brush which fully covers the sanding pad (34) on the circumferential direction.
The multi-sander kit of claim 6, wherein the rim of brush has a larger dimension compared to the sanding pad along the axial direction of the driving shaft.
The multi-sander kit of claim 6 or 7, wherein the rim of brush comprises nylon strip brushes.
The multi-sander kit of any one of the preceding claims, wherein the sanding pad (34) has a substantial truncated cone shape.
The multi-sander kit of any one of claims 1 to 8, wherein the sanding pad has a polygonal cross-sectional shape.
The multi-sander kit of claim 10, wherein the sanding pad has a rectangular cross-sectional shape.