AU2006203673B2 - Powered paint removal tool - Google Patents

Description

S&F Ref: 775761 AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name and Address Wagner Spray Tech Corporation, of 1770 Fernbrook Lane, of Applicant : Minneapolis, Minnesota, 55447, United States of America Actual Inventor(s): Jeffrey S. Jerdee Victor J. Fageroos Michael B. Jones Paul Derek Hatch Christopher Kent Barmore Gregory Edward Reinecker Address for Service: Spruson & Ferguson St Martins Tower Level 35 31 Market Street Sydney NSW 2000 (CCN 3710000177) Invention Title: Powered paint removal tool The following statement is a full description of this invention, including the best method of performing it known to me/us:- TITLE OF THE INVENTION Powered Paint Removal Tool BACKGROUND OF THE INVENTION [00011 The present invention relates to the field of tools and processes for removing protective coatings from architectural surfaces in preparation for recoating. [00021 A number of approaches to preparing previously coated surfaces for recoating are known. Typically paint is the coating to be removed, and as used herein, "paint" is to be understood to refer to any coating similar or identical to paint at least a portion of which is to be removed in the process of preparing the surface for recoating, again typically using paint. Specifically, one other coating included within the meaning of "paint" as used herein is stain. [00031 Among the prior art paint removal approaches are certain powered devices such as a heat gun (for use with a putty knife or scraper), an infrared heat source sold under the name "Silent Paint Remover," a rotary cutter sold under the name "Paint Shaver," and a rotary grinder sold under the name "Power Paint Remover." In addition to powered products, manual products and processes have been known, such as carbide scrapers, chemical paint strippers, powered washers using a water stream of 1500 to 4000 psi at 2 to 4 GPM (with pressures at about 4000 psi needed to remove paint), and various sanding appliances, wire brushes and other such abrasives. As is also known, each of these prior art approaches have various shortcomings, including substantial manual effort, operator skill, potential damage to the substrate from which the paint is to be removed, and, in some instances, increased time to prepare the previously coated surface for recoating. [00041 While it is known that electric drills may be used with sanding disks, such drills generally operate in a speed range well below the operating speed of the paint removal tool of the present invention. Using a drill with a sanding disk is 2 substantially less efficient than using the paint removal tool of the present invention. As a result, there is a need for a more efficient paint removal tool. It is also known that angle grinders may be used to remove material using abrasives; however, such angle grinders generally operate in a speed range substantially 5 above the operating speed range of the paint removal tool of the present invention. Using an angle grinder to remove paint is not satisfactory, since the angle grinder is far too aggressive in removing material, and a user will not readily be able to avoid damaging the substrate when using an angle grinder to remove paint, because such tools are designed to remove much harder material, e.g., metal. As such, angle grinders have been found to be io unsatisfactory for paint removal from architectural surfaces, such as home siding and trim. OBJECT OF THE INVENTION It is the object of the present invention to substantially overcome or ameliorate 15 one or more of the disadvantages of the prior art. SUMMARY OF THE INVENTION The present invention provides a coating removal apparatus for at least partially removing a coating from a previously coated surface, the apparatus comprising: a rotating drive assembly providing rotational torque about a rotational axis; 20 a rotating disk having a generally planar abrasive surface and a centrally located non-circular cross section engagement portion; a coupling assembly attached to the rotating drive assembly for rotation therewith and having: a corresponding non-circular cross section drive surface positively coupled to the 25 engagement portion of the disk in a circumferential direction about the rotational axis and loosely coupled to the engagement portion of the disk in an angular direction with respect to the rotational axis for positively rotating the disk about the rotational axis while simultaneously allowing angular deflection of the disk with respect to the rotational axis; and 30 a resilient member located adjacent the disk and biasing the planar abrasive surface of the disk to be generally perpendicular to the rotational axis in the absence of external forces on the disk and allowing the disk to deflect out of perpendicular with the axis when an external force offset from the axis is applied to the disk while still rotating the disk.

3 Preferably, the disk is allowed to deflect up to an angle of about 1.5 degrees out of perpendicular with the rotational axis. Preferably, the coupling assembly includes a drive nut having a non-circular drive surface. 5 Preferably, the coupling assembly further includes a retaining nut, with the drive nut and the retaining nut located on opposite sides of the disk. Preferably, the retaining nut and the drive nut have opposed mating surfaces radially inward of the disk and each of the retaining nut and drive nut have a radially projecting flange with the flanges spaced apart by a predetermined distance when the io opposed mating surfaces are in contact with each other. Preferably, the predetermined distance is greater than a thickness of the engagement portion of the disk. Preferably,the resilient member is an 0-ring and one of the retaining nut and drive nut has an annular space for receiving and locating the 0-ring adjacent the disk. is Preferably, the rotating disk moves in a range of about 780 to about 4200 surface feet per minute with respect to a surface on which a coating is to be removed. Preferably, the abrasive surface of the rotating disk moves in a range of about 1047 to about 2356 surface feet per minute with respect to the previously coated surface when in contact with the surface on which the coating is to be removed. 20 Preferably, the rotating drive assembly includes a housing, and the apparatus further comprises a handle positionable to: a storage position adjacent the housing, and an operating position generally perpendicular to the housing. Preferably, the coating removal apparatus further comprises: means for urging 25 the handle towards the storage position. Preferably, the coating removal apparatus further comprises: a lock and release mechanism operable to retain the handle in the operating position and to selectively permit release of the handle from the operating position to enable movement of the handle toward the storage position. 30 Preferably, the lock and release mechanism is further operable to retain the handle in the storage position and to selectively permit release of the handle from the storage position to enable movement of the handle toward the operating position.

3a Preferably, the lock and release mechanism includes at least one pushbutton on the handle. Preferably, the pushbutton has a projection that moves with the handle and engages a first locking surface on the housing to lock the handle in the operating position. 5 Preferably, the housing has a second locking surface positioned to engage the projection on the pushbutton to lock the handle in the storage position. Preferably, the handle further includes resilient biasing means for urging the pushbutton to a lock position in which the projection overlaps the second surface when the handle is moved to the operating position. 10 Preferably, the pushbutton is manually movable from the lock position to a release position wherein the projection does not overlap with the second surface wherein the handle is released to move from the operating position toward the storage position. Preferably, the lock and release mechanism further includes a cam surface in the housing in contact with the projection of the pushbutton and operable to urge the handle is towards the storage position when the handle is intermediate the operating and storage positions. Preferably, the rotating drive assembly rotates the rotating disk about a rotational axis and the operating position of the handle is generally perpendicular to the rotational axis. 20 Preferably, the storage position of the handle is generally parallel to the rotational axis. BRIEF DESCRIPTION OF THE DRAWINGS A preferred embodiment of the present invention will now be described, by way of an example only, with reference to the accompanying drawings wherein: 25 Figure 1 is a perspective view of an apparatus useful in the practice of the present invention, with a handle shown in an operating position. Figure 2 is a side elevation view of the apparatus of Figure 1, with the handle shown in a storage position. Figure 3 is an exploded view of the apparatus of Figures 1 and 2, with parts 30 omitted. Figure 4 is a side elevation view of parts of a driving mechanism from Figure 3. Figure 5 is a section view taken along line 5-5 of Figure 4. Figure 6 is an exploded view showing the parts of the driving mechanism of Figure 4. 35 Figure 7 is a perspective view of a ring gear housing.

3b Figure 8 is a top plan view of the ring gear housing of Figure 7. Figure 9 is a first section view along line IX-IX of Figure 7. Figure 10 is a second section view long line X-X of Figure 7. Figure 11 is a perspective view of a pin carrier. 5 Figure 12 is a top plan view of the pin carrier of Figure 11. Figure 13 is a side elevation view of the pin carrier of Figure 11. Figure 14 is a section view taken along line XIV-XIV of Figure 12. Figure 15 is a perspective view of an output shaft housing. Figure 16 is a top plan view of the output shaft housing of Figure 15. 10 Figure 17 is a side elevation view of the output shaft housing of Figure 15. Figure 18 is a section view taken along line XVIII-XVIII of Figure 16. Figure 19 is a top plan view of an output shaft.

4 (00301 Figure 20 is a section view taken along line XX-XX of Figure 19. 100311 Figure 21 is a side elevation view of the output shaft of Figures 19 and 20. [00321 Figure 22 is a side elevation view of the output shaft of Figure 21, except with the part rotated 90 degrees about its axis. [00331 Figure 23 is a bottom plan view of the output shaft of Figures 19-22. [00341 Figure 24 is a top plan view of a subassembly of the output shaft with an output bearing. 10035] Figure 25 is a simplified section view taken along line XXV-XXV of the subassembly of Figure 24. 100361 Figure 26 is an exploded view of an abrasive disk and mounting parts useful in the practice of the present invention. [00371 Figure 27 is a top plan view of a disk retaining nut. 100381 Figure 28 is a side elevation section view of the disk retaining nut taken along line XXVIII-XXVIII of Figure 27. [00391 Figure 29 is a top plan view of the abrasive disk from Figure 26. [00401 Figure 30 is a side elevation section view of the disk of Figure 26 taken along line XXX-XXX of Figure 30. [00411 Figure 31 is an enlarged perspective view of a disk drive nut from Figure 26. [00421 Figure 32 is a top plan view of the disk drive nut of Figure 31. [0043) Figure 33 is a side elevation section view of the disk drive nut of Figure 31 taken along line XXXIII-XXXIII of Figure 32. 100441 Figure 34 is a top plan view of an assembly of parts shown in the exploded view of Figure 26. [00451 Figure 35 is a side elevation section view of the assembly of Figure 34 taken along line XXXV-XXXV, with the disk aligned perpendicularly to an axis of rotation.

5 [00461 Figure 36 is an enlarged fragmentary view of detail XXXVI of Figure 35 with the O-ring omitted from one side and with the disk partially cutaway to more clearly illustrate certain aspects of the present invention. 100471 Figure 37 is a view similar to that of Figure 35, except with the disk shown out of perpendicularity with the axis of rotation. [00481 Figure 38 is an enlarged fragmentary view of detail XXXVIII of Figure 37. [00491 Figure 39 is a perspective view of the outside of a left housing half. [00501 Figure 40 is a perspective view of the inside of the left housing half of Figure 39. 100511 Figure 41 is a perspective view of the outside of a right housing half. 100521 Figure 42 is a perspective view of the inside of the right housing half of Figure 41. [00531 Figure 43 is a bottom plan view of a disk guard useful in the practice of the present invention. [00541 Figure 44 is a side elevation view of the disk guard of Figure 43, with a portion shown in section taken along line XLIV-XLIV in Figure 43. [0055] Figure 45 is a top plan view of the disk guard of Figure 43. [0056] Figure 46 is a side elevation section view of the disk guard taken along line XLVI-XLVI of Figure 45. [00571 Figure 47 is an enlarged perspective view of the disk guard. (00581 Figure 48 is an exploded view of a handle useful in the practice of the present invention. 100591 Figure 49 is a perspective view of the handle of Figure 48, along with locking pins and springs in an exploded subassembly view. [0060] Figure 50 is an enlarged end view of one of the locking pins from Figure 48. 100611 Figure 51 is a section view of the locking pin taken along line LI-LI of Figure 50. [00621 Figure 52 is a side view Qf the locking pin of Figures 50 and 51.

6 100631 Figure 53 is an enlarged detail view LIII from Figure 39 of a portion of the left housing half together with a corresponding pushbutton showing a lock and release arrangement for the handle of the present invention. 100641 Figure 54 is an enlarged detail view LIV from Figure 53. DETAILED DESCRIPTION OF THE INVENTION 100651 Referring now to the Figures, and most particularly to Figures 1 and 2, a powered paint removal tool 10 useful in the practice of the present invention may be seen. Tool or apparatus 10 is shown with a handle 12 in an operating position 14 in Figure 1, and with the handle 12 in a storage position 16 in Figure 2. 100661 Apparatus 10 has an electric motor 17 (see Figure 3) powered through cord 18 and an ON-OFF switch 20. When operating, the tool or apparatus 10 rotates an abrasive disk 22 about a rotational axis 24. The operating position 14 of the handle 12 is preferably located along an operating axis 26 approximately perpendicular to the rotational axis 24. The storage position 16 of the handle 12 is preferably approximately parallel to rotational axis 24, indicated by storage axis 28 in Figure 2. [00671 The tool 10 may also have a strap 30 spaced apart from a housing 32. A user may place one hand between the housing 32 and the strap 30 with the palm facing the housing 32 while using the tool 10. Simultaneously, the user may place the other hand on the handle 12. A third gripping location (for either hand) is a generally ovoid or egg-shaped top 34 of the housing 32. [0068] Referring now most particularly to Figure 3, housing 32 preferably includes a left half 36, a right half 38 and a disk guard 40. A locking pin assembly 42 is mounted in the left housing half 36 and biased radially outward from the rotation axis 24 by a spring 44, and retained to the housing by a pushnut 46. A wire bail 48 may be used to secure one end of the strap 30 to the housing 36, with the other end of the _strap 30 received around a pair of aligned bosses 50, 52 in the housing halves 36, 38 and which may be seen more clearly in Figures 39 and 42.

7 [00691 Motor 17 is preferably a universal type motor and includes an armature assembly 54, a field assembly 56, and a pair of brush assemblies 58 that, in operation, bear against a commutator 59. Motor 17 also includes a conventional fan 60 (shown only in outline), it being understood that fan 60 will draw cooling air in through vents 62, 64 in the housing 32 (see Figures 1 and 2). Air will then move axially along the armature assembly 54 and field assembly 56. Motor 17 is preferably rated at 400 Watts and rotates clockwise when viewed from the end nearest the commutator 59. [0070] Referring now to Figures 3-25, and most particularly initially to Figures 4-6, a rotating drive assembly 66 may be seen which includes the motor 17 and a gear subassembly 68. Motor output shaft 70 has gear teeth formed integral therewith and serves as an input sun gear for the gear subassembly 68. Gear subassembly 68 has a ring gear housing 72 with an internal ring gear 73 formed therein, three planet gears 74, each received on a pin 76 of a carrier and pin assembly 78. Gear subassembly 68 also has an output housing 80 and an output shaft and bearing assembly 82. The ring gear housing 72 is preferably threaded into the output housing 80 which itself is held stationary in housing 32 during operation of the tool 10. [00711 Referring now most particularly to Figures 7-10, the ring gear housing 72 has external threads 84 with a pair of diametrically located flats 86 therein useful in eliminating flashing that might otherwise occur during the molding process. Housing 72 also has three ribs equidistantly spaced on the periphery thereof to provide a centering function when the ring gear housing is assembled to the output housing 80. Housing 72 may be formed of polyhexamethylene adipamide (nylon 66). [0072] Referring now to Figures I1 - 14, the carrier and pin assembly 78 may be seen. Pins 76 are preferably press-fit into a carrier plate 77 to form assembly 78. Carrier plate 77 preferably has a hub 88 with a pair of flats 90. The carrier plate 77 may be formed of powered metal, and the pins 76 may be conventional dowel pins formed of steel. 100731 Referring now to Figures 15 -18, the output housing 80 may be seen in more detail. Housing 80 may be formed of nylon 6/6, and preferably has internal 8 threads 92 to mate with external threads 84 on housing 72. A first antifriction bearing 91 (see Figure 5) is preferably pressed into a relief 93 in the housing 80 to support an output shaft 94 which is subsequently fitted into bearing 91 in a light press fit. 100741 Referring now to Figures 19 - 25, various details of the output shaft and bearing assembly 82 may be seen. The output shaft 94 carries a second antifriction bearing 96 as an output bearing. Shaft 94 preferably has a pair of flats 98 arranged to mate with flats 90 in the hub 88 of carrier plate 77. Output shaft 94 has output threads 102 formed on the end thereof, and may have a transverse through bore 104. Bore 104 is sized and located to receive the radially inwardly directed end of the locking pin assembly 42 (see Figure 3) when the assembly 42 is moved manually radially inward against spring 44. Engagement of assembly 42 in bore 104 locks the output shaft 94 against rotation to permit installation and removal of the abrasive disk 22. Once the locking pin assembly 42 is released, spring 44 will move the assembly 42 radially outward to a position providing clearance between assembly 42 and output shaft 94. [00751 Referring now to Figures 26 - 38 various aspects of the mounting arrangement for the abrasive disk 22 may be seen. Figure 26 shows an exploded view of a coupling assembly 110 with the disk 22 and Figure 35 shows a cross section view of the coupling assembly 110 assembled with the disk 22. Coupling assembly 110 may include a retaining nut 112, a disk drive nut 114 and an O-ring 116. [0076] Retaining nut 112 has a hexagonal extension 118, a radially extending flange 120 defining an annular groove 122 and internal threads 124. Groove 122 is sized to receive and retain the 0-ring 116. 100771 Referencing now most particularly to Figures 29 and 30, abrasive disk 22 has an annular spun fiber abrasive filament section 126 with a generally planar abrasive surface 128. Section 126 may be mounted to a planar support layer 130 via an intermediate layer 132. Support layer 130 preferably has a non-circular cross section engagement portion 134 which preferably is a hexagonal aperture. Support layer 130 has a characteristic thickness 135 which may be about 0.05 inches. As may be seen in Figure 35, abrasive filament section 126 may have a thickness 137 of about 9 0.5 inches, with an outer diameter 141 of about 4.5 inches and an inner diameter 143 of about 2 inches. The material for section 126 is the same as that available from Minnesota Mining and Manufacturing Company for 4 1/2" Clean-n-Strip disks offered under the trademark SandBlaster, part number 9681, for angle grinders. [00781 It is to be understood that in one aspect, the present invention includes the powered drive assembly 66 and the rotating disk 22 driven by the powered drive assembly and having the generally planar abrasive surface 128 wherein the rotating disk moves in a range of about 780 to about 4200 surface feet per minute with respect to the previously coated surface when the tool 10 is loaded by being in contact with the surface on which the coating is to be removed. It is to be understood that the surface speeds mentioned correspond to a range of about 1500 to about 3500 RPM, but that the significant parameter is the actual relative speed between the disk and the surface being treated with the tool 10. As such, it is within the scope of the present invention to achieve the surface feet per minute range by varying either the RPM or the diameter of the disk to achieve the desired surface feet per minute. In practice, it has been found most preferable to operate at 2000 RPM with a disk having an OD of 4.5 inches and an ID of 2 inches, such that the relative speed is between about 1047 surface feet per minute (at the inside of the abrasive section 126) and about 2356 surface feet per minute (at the outside edge of the abrasive section 126) with the tool at its rated torque load. [00791 Referring now to Figures 31 - 33, various views of the disk drive nut 114 may be seen. Disk drive nut 114 has a non-circular cross-section drive surface 136 preferably in the form of a hexagonal boss corresponding to the non-circular cross-section engagement portion 134 suitable to receive and rotatingly drive the disk 22, while simultaneously allowing angular deflection of the disk with respect to the rotational axis as will be described in more detail, infra. Nut 114 also has a radially projecting flange 138 and a set of internal threads 139 sized to mate with the output threads 102 of the output shaft 94. Nut 114 also has a set of external threads 140 sized to mate with internal threads 124 of the retaining nut 112. As may best be seen in Figure 33, nut 114 also has a shoulder 142 spaced a predetermined distance 144 10 apart from flange 138. The predetermined distance 144 is greater than the thickness of the support layer 130 of the disk 22, to permit disk 22 to "float" in an axial direction parallel to the rotational axis 24. Preferably, for the embodiment shown, distance 144 is about 4.5 millimeters. Each of the retaining nut 112 and the disk drive nut 114 may be made of 30-33% glass filled nylon. In the practice of the present invention, it has been found preferably to secure the retaining nut 112 to the disk drive nut 114 using an epoxy as a thread sealer or binder between threads 124 and 140 after the coupling assembly 110 (including O-ring 116) is assembled to the disk 22. 100801 Referring now to Figures 34 - 38 various views of the combination of the disk 22 and coupling assembly 110 are presented to better illustrate certain aspects of the present invention. Figure 34 shows a top plan view of the coupling assembly 110 and disk 22. Figure 35 is a side elevation section view taken along line XXXV XXXV of Figure 34, with the disk 22 aligned perpendicularly to an axis of rotation 24. Figure 36 is an enlarged fragmentary view of detail XXXVI of Figure 35, except with the O-ring 116 omitted from one side and with the support layer 130 of disk 22 partially cutaway to more clearly illustrate certain aspects of the present invention. Figure 37 is a view similar to that of Figure 35, except with the disk 22 shown out of perpendicularity with the rotational axis 24, as it would appear when an external force offset from the axis 24 is applied to the disk 22, e.g., as may happen during operation of tool 10 when the tool 10 is tilted (either intentionally or unintentionally) to a position wherein the rotational axis 24 is not perpendicular to a plane of the surface on which a coating is being removed. Figure 38 is an enlarged fragmentary view of detail XXXVIII of Figure 37, and shows that in this condition (with an external unbalanced force applied) disk 22 (including layer 130) is permitted to deflect out of perpendicularity with the rotational axis 24, it being understood that the coupling assembly 110 continues to rotate the disk 22 during this condition. [0081] The present invention has been found to be satisfactory when an angular misalignment (represented by angle 146 in Figure 38) of up to about 1.5 degrees is permitted.

11 (00821 In this aspect, the present invention may be seen to be a coating removal apparatus for at least partially removing a coating from a previously coated surface including the rotating drive assembly 66 providing rotational torque about the rotational axis 24, the rotating disk 22 having the generally planar abrasive surface 128 and the centrally located non-circular cross-section engagement portion 134. The invention also includes the coupling assembly I 10 attached to the rotating drive assembly 66. The coupling assembly 110 preferably has the corresponding non circular cross-section drive surface 136 positively coupled to the engagement portion 134 of the disk 22 in a circumferential direction about the rotational axis 24 and loosely coupled to the engagement portion of the disk in an angular direction with respect to the rotational axis 24 for both positively rotating the disk 22 about the rotational axis 24 while simultaneously allowing angular deflection of the disk (e.g. along angle 146) with respect to the rotational axis 24. The coupling assembly also includes the resilient member 116 located adjacent the disk 22 to bias the planar abrasive surface 128 of the disk 22 to be generally perpendicular to the rotational axis 24 in the absence of external forces on the disk 22, as shown e.g., in Figure 35. The resilient member 116 also allows the disk 22 to deflect out of perpendicular with the axis 24 when an external force (offset from the axis 24) is applied to the disk even while the disk is rotating. The coupling assembly 110 may include the drive nut 114 with its non-circular drive surface 136. The coupling assembly 110 may further include the retaining nut 112, with the drive nut 114 and the retaining nut 112 located on opposite sides of the disk 22. The retaining nut and the drive nut may have opposed mating surfaces 142, 145 radially inward of the disk 22. Each of the retaining nut and drive nut preferably have radially projecting flanges 138, 120 with the flanges spaced apart by the predetermined distance 144 when the opposed mating surfaces 142 and 145 are in contact with each other. The retaining nut 112 may have annular space 122 for receiving and locating the O-ring 116 adjacent the disk 22. [00831 Referring now to Figures 39 - 47, various views of the housing 32 may be seen. The housing 32 is made up of the left housing half 36, the right housing half 38, and the disk guard 40. The inside of left and right halves 36, 38 may be seen, 12 respectively in Figures 39 and 42, illustrating details for mounting the drive assembly and other parts internal to the tool 10. The outside of left and right halves 36, 38 may be seen in Figures 40 and 41, respectively. It is to be understood that halves 36 and 38 are preferably molded of a relatively rigid polymer material, such as glass-filled polypropylene. Guard 40 may be molded of conventional polypropylene. In addition, right and left halves 36 and 38 are preferably overmolded with 0.07 inch thick layer of a softer polymer material such as a thermoplastic polymer in the regions marked with hatching. One suitable overmolding material is available under the trademark Santoprene type 8211-65 available from ADVANCED ELASTOMER SYSTEMS, L.P. of 388 S. Main Street, Akron Ohio 44311-1059. Such overmolding provides "soft-grip" features for those parts of the housing 32 normally contacted by a user's hands when operating the tool 10. [00841 Figures 43 - 47 show various views of the disk guard 40 which is preferably secured to the right and left halves 38, 36 of the housing 32 by horizontally extending fingers received in respective recesses 150 as the right and left halves 38, 36 are assembled together. 100851 Referring now to Figures 48 - 52, various views of the handle 12 and associated parts may be seen. Handle 12 is preferably made up of two halves 152, 154, each of which is preferably formed of polypropylene and partially overmolded with the same or similar material as with the main housing 32, to provide a "soft-grip" feature similar to the main housing 32. Figures 48 and 49 show the handle with overmolded polymer portions 156, 158 present. [00861 Figures 49 - 54 show details of a lock and release mechanism 160 for the handle 12, to lock the handle 12 in either the operating position 14 (Figure 1) or the storage position 16 (Figure 2). The mechanism 160 may be used to release the handle from either of positions 12 or 14 to move it to the other position. In addition, mechanism 160 has a feature which urges the handle 12 towards the storage position 14 when the handle is intermediate the operating and storage positions. In Figure 49, a pair of pushbuttons 162 (which are preferably identical) are received in recesses 164 (also preferably identical) in the handle 12, and each pushbutton is urged outward 13 from the handle 12, respectively, by a spring 166. The assembly shown in Figure 49 is received between the right and left housing halves 38, 36 when the housing 32 is assembled. It is to be understood that mechanism 160 includes features from the handle 12, the pushbutton 162 and cooperating surfaces in the right and left housing halves 38, 36, as will be described infra. Referring now particularly to Figures 50 52, each pushbutton has a generally cylindrical body 168 with a first projection 170 and a second projection 172, each of which are formed integrally with the body 168 and each of which thus will move with the handle 12 when the handle 12 is rotated with respect to the housing 32. First projection 170 is received in a first slot 174 in the handle 12 and the second projection 172 is received in a second slot 176 in the handle 12. [00871 Figure 53 shows another view of parts for the lock and release mechanism 160. In Figure 53, the button 162 has projections 170 and 172 shown in solid lines to illustrate the orientation of the button 162 when the handle is in the operating position 14, as shown in Figure 1. Projections 170 and 172 are shown in dashed lines to illustrate the orientation of the pushbutton 162 when the handle is in the storage position 16 (Figure 2). Referring now also to Figure 54, first projection 170 will be received in a storage position slot 178 in the housing 32 when the handle 12 is in the storage position 16, and first projection 170 will be received in an operating position slot 180 when the handle 12 is in the operating position 14. At all times, the first projection remains partially engaged with the first slot 174 in handle 12. When the handle 12 is intermediate the storage and operating positions, an edge 188 of the first projection 170 will be in contact with a cam surface 182 on the housing 32. Because the cam surface is narrows when approaching the storage position, the action of springs 166 urging pushbuttons 162 outward urge first projection 170 against cam surface 182 when the handle is intermediate the operating and storage positions, and the handle 12 will be urged toward the storage position 16. [00881 In this aspect the present invention may be seen to include a powered drive assembly 66 having a housing 32, a rotating disk 22 driven by the powered driving assembly and having a generally planar abrasive surface 128; and a handle 12 14 positionable to a storage position 16 adjacent the housing, and (alternatively) to an operating position 14 generally perpendicular to the housing 32. In this aspect, the invention may further include means for urging the handle towards the storage position. 100891 The lock and release mechanism 160 is operable to retain the handle 12 in the operating position 14 and to selectively permit release of the handle 12 from the operating position 14 to enable movement of the handle 12 toward the storage position 16. The lock and release mechanism 160 is further operable to retain the handle 12 in the storage position 16 and to selectively permit release of the handle 12 from the storage position 16 to enable movement of the handle toward the operating position 14. The lock and release mechanism 160 may include at least one pushbutton 162 on the handle 12 and the pushbutton may have a projection 170 that moves with the handle and engages a first locking surface 184 on the housing to lock the handle in the operating position. The housing preferably has a second locking surface 186 positioned to engage the projection 170 on the pushbutton 162 to lock the handle 12 in the storage position 16. The spring 166 provides resilient biasing means for urging the pushbutton to a lock position in which the projection 170 overlaps the second locking surface 186 when the handle is moved to the operating position. The pushbutton 166 is manually movable from the lock position to a release position wherein the projection 170 does not overlap with the second surface 186 wherein the handle 12 is released to move from the operating position 14 toward the storage position 16. The lock and release mechanism 160 may further include a cam surface 182 in the housing 32 in contact with the edge 188 of the projection 170 of the pushbutton 162 and operable to urge the handle 12 towards the storage position 16 when the handle is intermediate the operating and storage positions. 100901 This invention is not to be taken as limited to all of the details thereof as modifications and variations thereof may be made without departing from the spirit or scope of the invention.

Claims (20)

1. A coating removal apparatus for at least partially removing a coating from a previously coated surface, the apparatus comprising: a rotating drive assembly providing rotational torque about a rotational axis; s a rotating disk having a generally planar abrasive surface and a centrally located non-circular cross section engagement portion; a coupling assembly attached to the rotating drive assembly for rotation therewith and having: a corresponding non-circular cross section drive surface positively coupled to the io engagement portion of the disk in a circumferential direction about the rotational axis and loosely coupled to the engagement portion of the disk in an angular direction with respect to the rotational axis for positively rotating the disk about the rotational axis while simultaneously allowing angular deflection of the disk with respect to the rotational axis; and is a resilient member located adjacent the disk and biasing the planar abrasive surface of the disk to be generally perpendicular to the rotational axis in the absence of external forces on the disk and allowing the disk to deflect out of perpendicular with the axis when an external force offset from the axis is applied to the disk while still rotating the disk. 20

2. The apparatus of claim 1, wherein the disk is allowed to deflect up to an angle of about 1.5 degrees out of perpendicular with the rotational axis.

3. The apparatus of claim 1, wherein the coupling assembly includes a drive nut having a non-circular drive surface.

4. The apparatus of claim 3, wherein the coupling assembly further 25 includes a retaining nut, with the drive nut and the retaining nut located on opposite sides of the disk.

5. The apparatus of claim 4, wherein the retaining nut and the drive nut have opposed mating surfaces radially inward of the disk and each of the retaining nut and drive nut have a radially projecting flange with the flanges spaced apart by a 30 predetermined distance when the opposed mating surfaces are in contact with each other.

6. The apparatus of claim 5, wherein the predetermined distance is greater than a thickness of the engagement portion of the disk.

7. The apparatus of claim 6, wherein the resilient member is an O-ring and one of the retaining nut and drive nut has an annular space for receiving and locating the 35 O-ring adjacent the disk. 16

8. The apparatus of claim 1, wherein the rotating disk moves in a range of about 780 to about 4200 surface feet per minute with respect to a surface on which a coating is to be removed.

9. The apparatus of claim 8, wherein the abrasive surface of the rotating 5 disk moves in a range of about 1047 to about 2356 surface feet per minute with respect to the previously coated surface when in contact with the surface on which the coating is to be removed.

10. The apparatus of claim 1, wherein the rotating drive assembly includes a housing, and the apparatus further comprises a handle positionable to: 10 a storage position adjacent the housing, and an operating position generally perpendicular to the housing.

11. The apparatus of claim 10, further comprising: means for urging the handle towards the storage position.

12. The apparatus of claim 10, further comprising: is a lock and release mechanism operable to retain the handle in the operating position and to selectively permit release of the handle from the operating position to enable movement of the handle toward the storage position.

13. The apparatus of claim 12, wherein the lock and release mechanism is further operable to retain the handle in the storage position and to selectively permit 20 release of the handle from the storage position to enable movement of the handle toward the operating position.

14. The apparatus of claim 12, wherein the lock and release mechanism includes at least one pushbutton on the handle.

15. The apparatus of claim 14, wherein the pushbutton has a projection that 25 moves with the handle and engages a first locking surface on the housing to lock the handle in the operating position.

16. The apparatus of claim 14, wherein the housing has a second locking surface positioned to engage the projection on the pushbutton to lock the handle in the storage position. 30

17. The apparatus of claim 15, wherein the handle further includes resilient biasing means for urging the pushbutton to a lock position in which the projection overlaps the second surface when the handle is moved to the operating position.

18. The apparatus of claim 17, wherein the pushbutton is manually movable from the lock position to a release position wherein the projection does not overlap with 17 the second surface, wherein the handle is released to move from the operating position toward the storage position.

19. The apparatus of claim 15, wherein the lock and release mechanism further includes a cam surface in the housing in contact with the projection of the 5 pushbutton and operable to urge the handle towards the storage position when the handle is intermediate the operating and storage positions.

20. A coating removal apparatus substantially as hereinbefore described with reference to the accompanying drawings. Dated 2 February 2010 Wagner Spray Tech Corporation Patent Attorneys for the Applicant/Nominated Person SPRUSON & FERGUSON