A HOLDING DEVICE FOR ABRASIVE STRIPS AND USE OF A HOLDING DEVICE

Abstract

Disclosed is a holding device (1) for abrasive strips (2). The holding device (1) comprises a drum (3) being substantially cylindrical and including a number of undercut axial grooves (4) extending from a first axial drum end (5) of the drum (3) toward a second axial drum end (6) of the drum (3), wherein one or more stops (7) are arranged to block at least a part of each of the number of undercut axial grooves (4) at the second axial drum end (6), wherein the drum (3) comprises a blind hole (8) in the centre of the first axial drum end (5), and wherein a non-circular engagement indentation (9) is formed in the centre of the bottom (10) of the blind hole (8). The holding device (1) also comprises a shaft (11) arranged coaxially with the drum (3), wherein the shaft (11) comprises a main shaft part (12) including a first axial shaft end (13) extending from the drum (3) and arranged for being connected to rotation drive means. The shaft (11) further comprises an external non-circular engagement structure (14) arranged at a second axial shaft end (15) of the main shaft part (12), wherein the external non-circular engagement structure (14) is arranged in the non-15 circular engagement indentation (9) to rotatably lock the shaft (11) to the drum (3), and wherein the greatest radial extent (GES) of the external non-circular engagement structure (14) is greater than the greatest radial extent (GEM) of the main shaft part (12). Furthermore, the holding device (1) comprises an end plug (16) being releasably connected to the drum (3), wherein the end plug (16) comprises a centre protrusion (17) extending into the blind hole (8) to restrict axial displacement of the external non-circular engagement structure (14) to substantially fixate an axial position of the shaft (11) in relation to the cylindrical drum (3) and wherein the end plug (16) further comprises groove blocking means (18) arranged to block at least a part of each of the number of undercut axial grooves (4) at the first axial drum end (5). Use of a holding device (1) is also disclosed.

Claims

1. A holding device for abrasive strips, said holding device comprising, a drum being substantially cylindrical and including a number of undercut axial grooves extending from a first axial drum end of said drum toward a second axial drum end of said drum, wherein one or more stops are arranged to block at least a part of each of said number of undercut axial grooves at said second axial drum end, wherein said drum comprises a blind hole in the centre of said first axial drum end, and wherein a non-circular engagement indentation is formed in the centre of the bottom of said blind hole, a shaft arranged coaxially with said drum, wherein said shaft comprises a main shaft part including a first axial shaft end extending from said drum and arranged for being connected to a rotation driver, wherein said shaft further comprises an external non-circular engagement structure arranged at a second axial shaft end of said main shaft part, wherein said external non-circular engagement structure is arranged in said non-circular engagement indentation to rotatably lock said shaft to said drum, and wherein the greatest radial extent of said external non-circular engagement structure is greater than the greatest radial extent of said main shaft part, and an end plug being releasably connected to said drum, wherein said end plug comprises a centre protrusion extending into said blind hole to restrict axial displacement of said external non-circular engagement structure to substantially fixate an axial position of said shaft in relation to said cylindrical drum and wherein said end plug further comprises a groove blocker arranged to block at least a part of each of said number of undercut axial grooves at said first axial drum end.

2. The holding device according to claim 1, wherein at least a part of said centre protrusion of said removable end plug is cylindrical and comprises external threading, wherein at least a part of said coaxial blind hole is cylindrical and comprises internal threading, and wherein said end plug is releasably connected to said drum by said internal threading meshing with said external threading.

3. The holding device according to claim 1, wherein said end plug comprises grip indentation or grip protrusions.

4. The holding device according to claim 1, wherein said drum and said end plug are made of a plastic material and wherein said shaft is made of metal.

5. The holding device according to claim 1, wherein said first axial shaft end is arranged to extend from said first axial drum end and wherein said main shaft part is extending through a centre through plug hole in said end plug.

6. The holding device according to claim 1, wherein said first axial shaft end is arranged to extend from said second axial drum end and wherein said main shaft part is extending through a centre through drum hole in said drum.

7. The holding device according to claim 1, wherein said one or more stops are formed integrally with said drum.

8. The holding device according to claim 1, wherein said holding device further comprises a fixator arranged to fixate said external non-circular engagement structure in said non-circular engagement indentation.

9. The holding device according to claim 1, wherein the greatest radial extent of said groove blocker is greater than the outer diameter of said drum.

10. A method of holding abrasive strips, wherein said method comprises forming the holding device according to claim 1, removing said end plug from said drum, placing abrasive strips in said number of undercut axial grooves in said drum, and reconnecting said end plug to said drum.

11. The holding device according to claim 2, wherein said end plug comprises grip indentation or grip protrusions.

Description

FIGURES

[0032] The invention will be described in the following with reference to the figures in which

[0033] FIG. 1 illustrates a drum with a shaft and a first embodiment of an external non-circular engagement structure arranged in a non-circular engagement indentation, as seen from the side,

[0034] FIG. 2 illustrates a second embodiment of an external non-circular engagement structure arranged in a non-circular engagement indentation, as seen in from the side,

[0035] FIG. 3 illustrates a third embodiment of an external non-circular engagement structure arranged in a non-circular engagement indentation, as seen in from the side,

[0036] FIG. 4 illustrates a drum, as seen in an isometric view,

[0037] FIG. 5 illustrates an end plug, as seen from the side,

[0038] FIG. 6 illustrates an end plug, as seen from the top,

[0039] FIG. 7 illustrates a holding device, as seen from the top,

[0040] FIG. 8 illustrates a cross section through the middle of a holding device with the shaft extending from the first axial drum end, as seen from the top, and

[0041] FIG. 9 illustrates a cross section through the middle of a holding device with the shaft extending from the second axial drum end, as seen from the top.

DETAILED DESCRIPTION OF RELATED ART

[0042] FIG. 1 illustrates a drum 3 with a shaft 11 and a first embodiment of an external non-circular engagement structure 14 arranged in a non-circular engagement indentation 9, as seen from the side, FIG. 2 illustrates a second embodiment of an external non-circular engagement structure 14 arranged in a non-circular engagement indentation 9, as seen in from the side and FIG. 3 illustrates a third embodiment of an external non-circular engagement structure 14 arranged in a non-circular engagement indentation 9, as seen in from the side.

[0043] In this embodiment of the invention the drum 3 is substantially cylindrical and the outer surface is in this embodiment provided with twelve undercut axial grooves 4 arranged to accommodate abrasive strips 2. However, in another embodiment the drum 3 could also or instead be provided with a polygonal cross sectione.g. eight sided, twelve sided, twenty sided or moreand/or the drum 3 could be provided with fewer undercut axial grooves 4such as ten, eight, six or even lessor the drum 3 could be provided with more undercut axial grooves 4such as fifteen, twenty, twenty-five or even more.

[0044] In this embodiment the undercut axial grooves 4 are formed as tracks that are wider at the bottom of the tracks than at the outer surface of the drum 3 and in this embodiment the base 28 of the abrasive strips 2 have substantially the same shape as the undercut axial grooves 4 so that the abrasive strips 2 may be slid into the undercut axial grooves 4 from one end of the drum 3 and so that the abrasive strips 2 are substantially locked against radial displacement when mounted in the undercut axial grooves 4. However, in another embodiment the undercut axial grooves 4 and/or the base 28 of the abrasive strips 2 could have another shape, such as dovetail shape, an undercut circle, the bottom of the tracks could be wider or have another shape or the undercut axial grooves 4 and/or the base 28 of the abrasive strips 2 could be formed in numerous other ways ensuring that the strips 2 are radially locked in the undercut axial grooves 4.

[0045] In this embodiment the drum is illustrated with only one abrasive strip 2 in one undercut axial groove 4, however during normal use of the holding device 1 as an abrasive tool, abrasive strips 2 would be provided in all the undercut axial grooves 4.

[0046] In this embodiment the abrasive strip 2 comprises an abrasive cloth 29 which on the backside is supported by bristles 30 made of a plastic material and the abrasive cloth 29 and the bristles 30 are mounted in and connected to a base 28 comprising bend sheet metal. However, in another embodiment the abrasive strip 2 could also or instead comprise abrasive paper, wire brushes or other, the bristles 30 could be made from natural hair, metal, or the bristles 30 could be omitted and/or the base could be moulded plastic, an extruded aluminium rail or other or any combination thereof.

[0047] As shown in FIGS. 7-9 the holding device 1 comprises the drum 3 and a shaft 11 rotatably locked to the drum 3 by means of an external non-circular engagement structure 14 of the shaft 11 engaging a non-circular engagement indentation 9 arranged in the centre at the bottom of a blind hole 8 arranged in one of the end faces of the drum 3. The holding device 1 further comprises an end plug 16 releasably connected to the drum 3, wherein the end plug 16 comprises a centre protrusion 17 extending into the blind hole 8 to restrict axial displacement of the external non-circular engagement structure 14. However, in the embodiments disclosed in FIGS. 1-3, the holding device 1 is disclosed without the end plug 16 so that the external non-circular engagement structure 14 of the shaft 11 can be seen engaging the non-circular engagement indentation 9 of the drum 3.

[0048] In all the embodiments disclosed in FIGS. 1-3 the non-circular engagement indentation 9 comprises radially extending engagement features 25 and the external non-circular engagement structure 14 comprises corresponding radially protruding engagement features 26. In FIG. 1 the external non-circular engagement structure 14 and the corresponding non-circular engagement indentation 9 are formed as a bolt-headi.e. the external non-circular engagement structure 14 and the corresponding non-circular engagement indentation 9 has a hexagonal shape where the radially extending engagement features 25 and the radially protruding engagement features 26 are the sides and corners of the hexagon. In the embodiment disclosed in FIG. 2 the external non-circular engagement structure 14 and the corresponding non-circular engagement indentation 9 are formed as an elongated rectanglei.e. the he radially extending engagement features 25 and the corresponding radially protruding engagement features 26 are the transversal protruding ends of the elongated rectangleand in the embodiment disclosed in FIG. 3 the external non-circular engagement structure 14 and the corresponding non-circular engagement indentation 9 are formed as an irregularly sided circle shapei.e. the radially extending engagement features 25 are in this case indentations in the sidewall of the non-circular engagement indentation 9 and the radially protruding engagement features 26 are the protrusions of the external non-circular engagement structure 14 of the shaft 11. However, in another embodiment the external non-circular engagement structure 14 and the corresponding non-circular engagement indentation 9 could be provided with numerous other non-circular shapes ensuring that the shaft 11 would be rotatably locked in relation to the drum 3. In another embodiment only parts of the external non-circular engagement structure 14 would correspond to the non-circular engagement indentation 9 as long as the external non-circular engagement structure 14 and the non-circular engagement indentation 9 are locked against mutual rotation.

[0049] In all the embodiments disclosed in FIGS. 1-3 the greatest radial extent GES of the external non-circular engagement structure 14 is greater than the greatest radial extent GEM of a main shaft part 12 of the shaft 11 to ensure that the shaft 11 can be locked against axial displacement in relation to the drum 3 as will be further discussed in relation to FIGS. 7-9.

[0050] FIG. 4 illustrates a drum 3, as seen in an isometric view.

[0051] In this embodiment the undercut axial grooves 4 are extending from a first axial drum end 5 of the drum 3 toward a second axial drum end 6 of the drum 3. I.e. in this embodiment the undercut axial grooves 4 are open and freely accessible at the first axial drum end 5 of the drum 3.

[0052] In this embodiment the drum 3 is provided with stops 7 at the end of undercut axial grooves 4 at the second axial drum end 6 of the drum 3. The stops 7 are provided to block each of the undercut axial grooves 4 to thereby restrict axial movement of the abrasive strips 2 in one direction when the abrasive strips 2 are mounted in the undercut axial grooves 4. In this embodiment the stops 7 are formed integrally with the drum 3 but in another embodiment the stops 7 could be formed as individual removable stops 7 or as a single e.g. removable part connected to the drum 3.

[0053] In this embodiment the drum 3 comprises a blind hole 8 coaxially arranged in the centre of the first axial drum end 5 and as disclosed in FIGS. 1-3 the non-circular engagement indentation 9 is located in the centre of the bottom 10 of the blind hole 8. In this embodiment the coaxial blind hole 8 is cylindrical and the sidewalls are provided with internal threading 20 enabling that the end plug 16 may be removably connected to the drum 3 through the threading as will discussed more in relation to FIGS. 5-6. However, if the end plug 16 was removably connected to drum 3 through other means than threading the blind hole 8 and/or the centre protrusion 17 of the end plug 16 could be non-circularsuch as square, oval, polygonal or other.

[0054] FIG. 5 illustrates an end plug 16, as seen from the side and FIG. 6 illustrates an end plug 16, as seen from the top.

[0055] In this embodiment the end plug 16 comprises a centre protrusion 17 adapted to correspond to the blind hole 8 of the drum 3, so that when the end plug 16 is connected to the drum 3, the centre protrusion 17 will substantially protrude all the way to the bottom of the blind hole 8. However, e.g. if the external non-circular engagement structure 14 of the shaft 11 was extending up and out of the non-circular engagement indentation 9, the centre protrusion 17 could be adapted to extend down to the external non-circular engagement structure 14.

[0056] In this embodiment the outer cylindrical surface of the centre protrusion 17 is provided with external threading 19 matching the internal threading 20 in the blind hole of the drum 3. I.e. in this embodiment the end plug 16 is releasably connected to the drum 3 through the matching threading 19, 20 but in another embodiment the end plug 16 could be releasably connected to the drum 3 through flexible flaps on the end plug 16 engaging corresponding slits or indentations in the drum 3 or vice versa or through another embodiment of a click-lock solution, the drum 3 or the end plug 16 could be provided with an O-ring engaging a matching groove in the opposite part, the end plug 16 could be releasably connected to the drum 3 through screws or other or the end plug 16 could be releasably connected to the drum 3 in a number of other ways.

[0057] In this embodiment the end plug 16 is also provided with groove blocking means 18 arranged to block the undercut axial grooves 4 at the first axial drum end 5 of the drum when the end plug 16 is connected to the drum 3as also disclosed in FIGS. 7-9. In the embodiment disclosed in FIGS. 5-6 the end plug 16 comprises grip indentation 21 enabling that a user may get a better grip on the end plug 16 when connecting or disconnecting the end plug 16 and in FIG. 6 the end plug 16 further comprises grip protrusions 22 arranged for the same purpose. However, in another embodiment the end plug 16 could also or instead comprise a high friction coating, a surface profile or other or any combination hereof for the same purpose.

[0058] FIG. 7 illustrates a holding device 1, as seen from the top and FIG. 8 illustrates a cross section through the middle of a holding device 1 with the shaft 11 extending from the first axial drum end 5, as seen from the top.

[0059] In this embodiment the substantially cylindrical drum 3 comprising the undercut axial grooves 4 includes the blind hole 8 in the centre of the first axial drum end 5 and the non-circular engagement indentation 9 is formed in the centre of the bottom of the blind hole 8. The shaft 11 comprises a main shaft part 12 having a first axial shaft end 13 is in this embodiment extending from the first axial drum end 5 of the drum 3 and the main shaft part 12 is extending through a centre through plug hole 23 in the end plug 16. In this embodiment the diameter of the centre through plug hole 23 is only a few tenths of a millimetre bigger than the outer diameter of the main shaft part 12 to enable that the end plug 16 may support the shaft 11 during use by preventing bending or deflection of the part of the shaft 11 extending through the end plug 16.

[0060] In this embodiment the shaft 11 further comprises an external non-circular engagement structure 14 arranged at the second axial shaft end 15 of the main shaft part 12 and the external non-circular engagement structure 14 is arranged in the non-circular engagement indentation 9 to rotatably lock the shaft 11 to the drum 3. In this embodiment the external non-circular engagement structure 14 and the corresponding non-circular engagement indentation 9 have a hexagonal shape as disclosed in FIG. 1 but as previously discussed in another embodiment the external non-circular engagement structure 14 and the corresponding non-circular engagement indentation 9 could have numerous other corresponding non-circular shapes.

[0061] In this embodiment the first axial shaft end 13 of the shaft 11 is connected to rotation drive means 31 in the form of a handheld power drill but in another embodiment the rotation drive means 31 could be any other kind of device capable of rotating the holding device 1.

[0062] In this embodiment the end plug 16 is releasably connected to the drum 3 by means of threading 19, 20 and the centre protrusion 17 of the end plug 16 is extending into the blind hole 8 to restrict axial displacement of the external non-circular engagement structure 14 in that the greatest radial extent GES of external non-circular engagement structure 14 is greater than the greatest radial extent GEM of the main shaft part 12 and in that the centre through plug hole 23 in the end plug 16 is only slightly bigger than the main shaft part 12 so that the centre protrusion 17 of the end plug 16 will press down on the external non-circular engagement structure 14 to substantially fixate the external non-circular engagement structure 14 in the non-circular engagement indentation 9 to maintain the axial position of the shaft 11 in relation to the drum 3.

[0063] In this embodiment the end plug 16 further comprises groove blocking means 18 arranged to block the undercut axial grooves 4 at the first axial drum end 5 and in this embodiment the greatest radial extent GEB of the groove blocking means 18 is greater than the outer diameter ODD of the drum 3 to ensure that at least parts of the groove blocking means 18 are wider than the drum 3 so that a used may more easily get a hold on the end plug 16 to unscrew the end plug 16 if the abrasive strips (not disclosed in these FIGS.) needed to be changed.

[0064] To reduce material use, weight, number of parts and cost the stops 7 at the second axial drum end 6 are in this embodiment formed integrally with the drum 3 and to enable this, the drum 3 is in this embodiment made by 3D printing of a plastic material. And given the relatively complex shape of the end plug 16, the end plug 16 is in this embodiment also made by 3D printing of a plastic material. However, in another embodiment the drum 3 and/or the end plug 16 could be made by moulding, machining or another process or any combination thereof.

[0065] In this embodiment the shaft 11 is made of metal in the form of steel to be able to transfer the torque and bending moments during use but in another embodiment the shaft could be made of brass, stainless steel, a fibre reinforces resin material, a composite material or other or any combination thereof.

[0066] In this embodiment the holding device 1 further comprises fixation means 27 in the form of adhesive arranged between the external non-circular engagement structure 14 and the non-circular engagement indentation 9 to hold them together so that the shaft 11 does not release from the drum 3 when the end plug 16 is removed. However, in another embodiment the fixation means 27 could comprise a radially extending set screw engaging the external non-circular engagement structure 14, an axially extending head screw, a dedicated holding device, a bayonet coupling device or other or any combination thereof.

[0067] FIG. 9 illustrates a cross section through the middle of a holding device 1 with the shaft 11 extending from the second axial shaft end 6, as seen from the top.

[0068] In this embodiment the first axial shaft end 13 is arranged to extend from the second axial drum end 6 of the drum 3 and in this embodiment the main shaft part 12 is therefore extending through a centre through drum hole 24 in the drum 3.

[0069] In this embodiment the diameter of the centre through drum hole 24 is only a few tenths of a millimetre bigger than the outer diameter of the main shaft part 12 to enable that the drum 3 may support the shaft 11 during use by preventing bending or deflection of the part of the shaft 11 extending through the drum 3.

[0070] The invention has been exemplified above with reference to specific examples of drums 3, shafts 11, end plugs 16 and other. However, it should be understood that the invention is not limited to the particular examples described above but may be designed and altered in a multitude of varieties within the scope of the invention as specified in the claims.

LIST

[0071] 1. Holding device [0072] 2. Abrasive strip [0073] 3. Drum [0074] 4. Undercut axial groove [0075] 5. First axial drum end [0076] 6. Second axial drum end [0077] 7. Stop [0078] 8. Blind hole [0079] 9. Non-circular engagement indentation [0080] 10. Bottom of blind hole [0081] 11. Shaft [0082] 12. Main shaft part [0083] 13. First axial shaft end [0084] 14. External non-circular engagement structure [0085] 15. Second axial shaft end [0086] 16. End plug [0087] 17. Centre protrusion of end plug [0088] 18. Groove blocking means [0089] 19. External threading [0090] 20. Internal threading [0091] 21. Grip indentation [0092] 22. Grip protrusion [0093] 23. Centre through plug hole in end plug [0094] 24. Centre through drum hole in drum [0095] 25. Radially extending engagement feature [0096] 26. Radially protruding engagement feature [0097] 27. Fixation means [0098] 28. Base of abrasive strip [0099] 29. Abrasive cloth [0100] 30. Brush [0101] 31. Rotation drive means [0102] GES. Greatest radial extent of external non-circular engagement structure [0103] GEM. Greatest radial extent of main shaft part [0104] GEB. Greatest radial extent of groove blocking means [0105] ODD. Outer diameter of drum