Patent Publication Number: US-7713110-B2

Title: Locking random orbital dual-action head assembly

Description:
FIELD OF THE INVENTION 
   The present invention relates generally to a lockable random orbital dual-action head assembly. More particularly, the present invention relates to a locking assembly arranged to lock a rotatable element to prevent rotation of the rotatable element relative to the head assembly about an axis of rotation. 
   BACKGROUND OF THE INVENTION 
   Orbital abrading tools are well-known and generally comprise a portable, manually manipulatable housing, a motor supported by the housing and having or being coupled to a drive shaft driven for rotation about a first axis, and an assembly for mounting a pad for abrading or polishing a work surface for orbital movement about the first axis. In a random orbital abrading tool, the assembly serves to additionally mount the pad for free rotational movement about a second axis, which is disposed parallel to the first axis. 
   The assembly typically includes a head portion coupled for driven rotation with the drive shaft about the first axis and defining a mounting recess having an axis arranged coincident with the second axis, a bearing supported within the mounting recess, and means for connecting the pad to the bearing for rotation about the second axis. 
   Locking mechanisms for orbital abrading tools are known in the art and described in U.S. Pat. No. 6,749,493 (Wuensch); U.S. Pat. No. 6,974,370 (Hutchins); U.S. Pat. No. 6,485,360 (Hutchins); and, U.S. Pat. No. 5,823,862 (Heidelberger. The locking mechanisms are also known as spindle-locks in the art. 
   U.S. Pat. No. 6,749,493 (Wuensch) discloses a spindle-lock using a circumferential slider to engage at least one pin to lock the mechanism. By moving the slider circumferentially, a spring retained pin will be forced to vertically engage a hole in a gear wheel, locking the spindle. Wuensch shows a one-piece design for both the motor assembly and the head assembly. Thus, a new tool would be necessary for use with a different head assembly (such as a non-orbital head or a grinder wheel). Furthermore, the circumferential slider comprises many components, increasing the cost of manufacturing and overall weight of the tool. 
   The same deficiency is present in both U.S. Pat. No. 6,485,360 (Hutchins), and U.S. Pat. No. 5,823,862 (Heidelberger). Although they have different forms of locking mechanisms, the locking mechanism, head assembly, and rotatable means about a second axis are permanently affixed to the abrading tool housing. This broad incorporation restricts the capabilities of the tool. Thus, a new tool would be necessary for use with a different head assembly (such as a non-orbital head or a grinder wheel). 
   U.S. Pat. No. 6,974,370 (Hutchins &#39;370) presents a similar deficiency. Hutchins &#39;370 shows a spindle lock for an orbital abrading or polishing tool. The head assembly is removable from the abrading tool, but the locking mechanism and means for orbital motion are structural components of the abrading tool housing. Thus, a new tool would still be necessary for a non-orbital head or a grinder wheel. 
   Furthermore, the locking mechanisms, or spindle-locks, described in the references above can be awkward to manipulate by a user wearing work gloves. Also, the locking mechanisms can be engaged accidentally by the user while the tool is in operation, resulting in excessive wear of the locking mechanism components and reducing the lifetime of the rotary tool and its components. 
   What is needed then is a locking random orbital dual-action head assembly wherein the rotatable means about an orbital axis and locking mechanism are structural components of the head assembly so that the head assembly can be used with a standard rotary tool. Thus, a single rotary tool can be used and different head assemblies can be attached for various uses. Also, costs can be reduced as individual head assemblies or rotary tools can be repaired or replaced independent of an entire head-assembly/rotary tool combination as in the prior art. 
   What is also needed is a head assembly comprising a locking mechanism that can not easily be accidentally locked while the tool is in operation, reducing unnecessary wear on the head assembly&#39;s or rotary tool&#39;s components. 
   SUMMARY OF THE INVENTION 
   The invention broadly comprises a removable head assembly for a rotary tool, including a body arranged for connection to a drive means, the drive means rotatable about a first axis of rotation; a rotatable element arranged for connection to a pad assembly, the rotatable element rotatable about a second axis of rotation disposed substantially parallel to the first axis of rotation; and, a locking assembly arranged to lock the rotatable element to the body to prevent rotation of the rotatable element relative to the body about the second axis of rotation. 
   In some aspects, the head assembly includes a first element displaceable to rotationally lock the rotatable element, and a second element engageable with the first element and displaceable to control the displacement of the first element and the locking assembly includes an elastically deformable element arranged to urge the first element in a first direction. The second element is engageable with the first element to urge the first element in a second direction, opposite the first direction, to lock the rotatable element with the body. 
   In some aspects, the rotatable element includes at least one receiving feature engageable with the first element, the pad assembly includes a pad base and an abrasive pad, or the pad base and the abrasive pad are secured to one another by means of a hook and loop fastening system. In some aspects, the removable head assembly includes a rotary tool. In some aspects, the rotary tool has an air powered motor. In some aspects, the removable head assembly includes a coupling for detachably securing the head assembly to a rotary tool and the coupling is a threaded connection or a socket connection. In some aspects, the removable head assembly includes a counterbalance secured to the body. 
   The invention also broadly comprises head assembly for a rotary tool including: a body connected to a drive means for the rotary tool, the drive means rotatable about a first axis of rotation; a rotation means disposed in the body for rotation about a second axis parallel to the first axis, the rotation means comprising a latitudinal portion extending substantially perpendicular to the second axis and comprising at least one receiving aperture; and, a locking mechanism comprising substantially longitudinal first and second components slidingly engaged with the body and slidingly engaged one with the other, wherein the first component is arranged to slide parallel to the latitudinal portion to displace the second component in a first direction substantially parallel to the second axis to engage the second latitudinal component with the at least one receiving aperture to rotationally lock the rotation means with respect to the body. 
   The invention further broadly comprises a combination rotary tool and removable head assembly, comprising: a rotary tool having a handle, drive means, and means for receiving a removable head assembly; and a removable head assembly operatively arranged to be detachably secured to the rotary tool. The assembly includes: a body arranged for connection to the drive means, the drive means rotatable about a first axis of rotation; a rotatable element arranged for connection to a pad assembly, the rotatable element rotatable about a second axis of rotation disposed substantially parallel to the first axis of rotation; and a locking assembly arranged to lock the rotatable element to the body to prevent rotation of the rotatable element relative to the body about the second axis of rotation. 
   The invention broadly comprises a combination rotary tool and head assembly, including: a rotary tool having a handle, drive means, and means for securing a head assembly; and, a head assembly secured to the rotary tool. The assembly includes: a body connected to a drive means for the rotary tool, the drive means rotatable about a first axis of rotation; a rotation means disposed in the body for rotation about a second axis parallel to the first axis, the rotation means comprising a latitudinal portion extending substantially perpendicular to the second axis and comprising at least one receiving aperture; and a locking mechanism including substantially longitudinal first and second components slidingly engaged with the body and slidingly engaged one with the other, wherein the first component is arranged to slide parallel to the latitudinal portion to displace the second component in a first direction substantially parallel to the second axis to engage the second latitudinal component with the at least one receiving aperture to rotationally lock the rotation means with respect to the body. 
   A general objective of the present invention is to provide a removable head assembly with a means for restricting orbital rotation. 
   A further object of the present invention is to minimize the size, weight, and cost of a locking random orbital dual-action head assembly. 
   These and other objects, features and advantages of the present invention will become readily apparent to those having ordinary skill in the art upon a reading of the following detailed description of the invention in view of the drawings and claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The nature and mode of operation of the present invention will now be more fully described in the following detailed description of the invention taken with the accompanying drawing figures, in which: 
       FIG. 1  is a perspective view of a present invention removable locking random orbital dual action head assembly connected to a rotary tool; 
       FIG. 2  is an exploded view of the removable locking random orbital dual action head assembly and rotary tool shown in  FIG. 1 ; 
       FIG. 3  is a front view of the removable locking random orbital dual action head assembly shown in  FIG. 1 ; 
       FIG. 4  is a cross sectional view of the removable locking random orbital dual action head assembly shown in  FIG. 3  taken along Line  4 - 4  in  FIG. 3 ; 
       FIG. 5  is a top view of the removable locking random orbital dual action head assembly shown in  FIG. 1 ; 
       FIG. 6  is a cross sectional view of the removable locking random orbital dual action head assembly shown in  FIG. 5  taken along Line  6 - 6  in  FIG. 5 ; 
       FIG. 7  is a top view of the sliding bolt shown in  FIG. 1 ; 
       FIG. 8  is a side view of the sliding bolt shown in  FIG. 7  taken along Line  8 - 8  in  FIG. 7 ; and, 
       FIG. 9  is an illustrative view of a present invention locking mechanism illustrating the sliding bolt of  FIG. 8  engaging a pin into an engagement hole. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   At the outset, it should be appreciated that like drawing numbers on different drawing views identify identical, or functionally similar, structural elements of the invention. While the present invention is described with respect to what is presently considered to be the preferred aspects, it is to be understood that the invention as claimed is not limited to the disclosed aspects. 
   Furthermore, it is understood that this invention is not limited to the particular methodology, materials and modifications described and as such may, of course, vary. It is also understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to limit the scope of the present invention, which is limited only by the appended claims. 
   Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs. Although any methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the invention, the preferred methods, devices, and materials are now described. 
     FIG. 1  is a perspective view of rotary tool  10  connected to removable locking random orbital dual action head assembly  20  (hereinafter “head assembly  20 ”). Rotary tool  10  in a preferred embodiment is a compressed air powered tool, but it should be appreciated that any type of rotary tool could be used. For example, an electrically powered rotary tool could be used. In a preferred embodiment, rotary tool  10  comprises first handle  12 , second handle  14 , and trigger  16 , which triggers air flow to provide power to rotary tool  10 . 
     FIG. 2  is an exploded view of removable locking random orbital dual action head assembly  20  and rotary tool  10  shown in  FIG. 1 . 
     FIG. 3  is a front view of removable locking random orbital dual action head assembly  20  shown in  FIG. 1 . 
     FIG. 4  is a cross sectional view of removable locking random orbital dual action head assembly  20  shown in  FIG. 3  taken along Line  4 - 4  in  FIG. 3 . The following should be viewed in light of  FIGS. 1 through 4 . Rotary tool  10  includes threaded screw  18  for attachment to head assembly  20  at threaded port  28 . This connection at threaded screw  18  and threaded port  28  provides first axis of rotation  52  for orbital motion. First axis of rotation  52  is most clearly shown in  FIG. 4 . Referring back to  FIG. 2 , it should be appreciated that any means between rotary tool  10  and head assembly  20  could be used. A threaded connection is preferred, but a socket connection (such as a connection used for socket wrenches as known in the art) or any other form of coupling known in the art used in rotation applications could be used. 
   The following is a broad overview of assembly  20 , further details are provided below. Assembly  20  includes body, or casing  30 , rotatable element, or spindle,  36 , and locking assembly  21 . Casing  30  is arranged for connection to a drive means, for example, screw  18 , rotatable about a axis of rotation  52 . Element  36  is arranged for connection to a pad assembly, for example pad assembly  45 , and is rotatable about axis of rotation  54 , disposed substantially parallel to axis of rotation  52 . Locking assembly  21  is arranged to lock rotatable element  36  to body  30  to prevent rotation of element  36 , relative to body  30 , about axis of rotation  54 . 
   Locking assembly  21  includes element, or pin,  26  displaceable to rotationally lock rotatable element  36 . Assembly  21  also includes element  22 , engageable with element  26  and displaceable to control the displacement of element  26 , and elastically deformable element  25  arranged to urge element  26  in direction  23 . In some aspects, element  25  is a spring. However it should be understood that any elastically deformable element known in the art can be used. As further described below, element  22  is engageable with element  26  to urge element  26  in direction  29 , to lock element  36  with body  30 . Rotatable element  36  includes at least one receiving feature engageable with element  26 . The receiving feature can be an opening, for example, opening  37 , or an indentation. 
   Casing  30  of assembly  20  includes threaded port  28 , pin hole  32 , and sliding bolt hole  24 . Pin hole  32  is operatively arranged to accept pin  26  and retention spring  25 . Retention spring  25  retains pin  26  in a disengaged position, with respect to element  36 , until sliding bolt  22  is engaged. 
   Pin  26  includes rib  27 , upon which retention spring  25  rests. Sliding bolt hole  24  is operatively arranged to accept sliding bolt  22 . In some aspects, sliding bolt  22  protrudes through both sides of sliding bolt hole  24  so that an operator can access both ends of slide sliding bolt  22  to move the bolt from an engaged to a disengaged position. In some aspects, sliding bolt  22  protrudes through one side substantially more so that the other side dependent upon whether sliding bolt  22  is in the engaged or disengaged position. Sliding bolt  22  protrudes through to a first side substantially more than a second side in the engaged position, and protrudes through the second side substantially more than the first side in the disengaged position. The engaged and disengaged positions are further described below. The preceding configuration enables easy engagement or disengagement of the sliding bolt  22  when the operator is wearing work gloves. 
   Sliding bolt  22  rotates with head assembly  20  when rotary tool  10  is engaged. This rotation inhibits a user from accidentally engaging sliding bolt  22  while the tool is being used and causing unnecessary wear on the components. 
   Casing  30  acts as a shell and structural support for ball bearing assembly  34 , spindle  36 , and counterbalance  40 . Ball bearing assembly  34  provides for rotation, about axis  54 , of spindle  36 , base support  44 , pad base  45  and pad  48  independent of casing  30 . It should be appreciated that any ball bearing means known in the art can be used for ball bearing assembly  34 . It also should be appreciated that any rotation support means known in the art can be used for rotation about axis  54 , for example a bushing arrangement (not shown). 
   In some aspects, spindle  36  includes a plurality of holes or indentations. Some of the holes, for example, holes  37 , are engagement holes and some of the holes, for example, holes  39  are bearing retention holes. It should be appreciated that any number of holes could be used. In some aspects, three holes for engagement holes  37  and three holes for retention holes  39  are used for ease of balancing and manufacturing. Balancing is very important in rotary tools in order to minimize undesirable vibration. Engagement holes  37  are about the same size as the diameter of pin  26  and are operatively arranged to accept pin  26 . Retention holes  39  are of a size larger that the heads of retention screws  38 . Retention screws  38  hold ball bearing assembly  34  to casing  30 . It should be appreciated that any means of attachment known in the art can be used. In some aspects, retention screws  38  in a set of three are used for balancing and ease of manufacturing. Pin hole  32  and holes  37  are at a same radial distance from axis  54  to facilitate the alignment of pin  26  and the holes as further described below. 
   In some aspects, counterbalance  40  is bolted into casing  30  by means of bolts  42  to provide a balanced rotation of both orbital and rotational motion and thereby reduce vibrations. 
     FIG. 5  is a top view of removable locking random orbital dual action head assembly  20  shown in  FIG. 1 . 
     FIG. 6  is a cross sectional view of removable locking random orbital dual action head assembly  20  shown in  FIG. 5  taken along Line  6 - 6  in  FIG. 5 . 
     FIG. 7  is a top view of sliding bolt  22  shown in  FIG. 1 . 
     FIG. 8  is a side view of sliding bolt  22  shown in  FIG. 7  taken along Line  8 - 8  in  FIG. 7 . 
     FIG. 9  is an illustrative view of present invention locking assembly, or locking mechanism,  21  illustrating sliding bolt  22  of  FIG. 8  engaging pin  26  to urge pin  26  into an engagement hole. The following should be viewed in light of  FIGS. 1 through 9 . The operation of locking assembly  21  is now described in further detail. Sliding bolt  22  has two graduated slots, slot  62  for a disengaged position of pin  26 , and slot  64  for an engaged position of pin  26 . Ridge  66  is disposed between slots  62  and  64 . Ridge  66  inhibits bolt  26  from moving between slots  62  and  64 , thereby helping to prevent sliding bolt  22  from sliding pin  26  between engaged slot  64  and disengaged slot  62  without direct user manipulation to overcome the spring force created by retention spring  25 . In  FIGS. 4 and 6 , sliding bolt  22  is in a disengaged position with pin  26  in slot  62 . Slots  62  and  64 , with ridge  66  between them, has been previously presented in U.S. Pat. No. 5,823,862 (Heidelberger), which is incorporated by reference herein. 
   As noted above, elastically deformable element, or spring,  25  applies constant force to pin  26  to urge the pin in direction  23 . This force tends to keep pin  26  engaged with which ever of slots  62  or  64  in which the pin is disposed. In the unlocked mode, pin  22  is positioned so that pin  26  is disposed in slot  62 . Length  31  of pin  26  is less than or equal to axial length  33  between pin  22  and element  36 , so that in the unlocked mode, pin  26  does not extend far enough in direction  29  to engage element  36  and element  36  is able to rotate without substantive interference from pin  26 . 
   To switch to the locking mode, pin  22  is laterally displaced so that pin  26  shifts to slot  64 , displacing pin in direction  29  and into opening  37 , as shown in  FIG. 9 . For example, length  31  is sufficient to enable pin  26  to extend through opening  37  once pin  26  and opening  37  are aligned. To attain this alignment from the unlocked position, lateral pressure is applied to the appropriate end of pin  22 , for example, in direction  74  in  FIG. 9  and assembly  20  (and subsequently element  36 ) is rotated about axis  54  until an opening  37  aligns with pin  26 . At that point, the lateral pressure causes pin  22  to slide so that pin  26  displaces to slot  64  and is pushed into opening  37 , locking element  37  with respect to casing  30  through which pin  26  passes. Thus, by rotating head assembly  20  around second axis  54 , pin  26  will eventually align with one of the three engagement holes  37 . 
   The locking mechanism herein described locks the rotation of the pad assembly, which comprises base support  44 , pad base  45 , and pad  48  about second axis  54 . Thus, the pad assembly will only rotate about first axis  52  with casing  30 . 
   In some aspects, components of head assembly  20  are machined from metal. In some aspects, other material including, but not limited to composites, plastics, and combinations thereof are used to make the components. In some aspects both metal and one or more of the other materials are used to form the components. It should also appreciated that any form of metal processing could be used, including casting, pressing, welding, machining, and combinations thereof. In some aspects, machining is used to increase precision. 
   Base support  44  and pad base  45  are affixed to each other by glue, but it should be appreciated that any means of attachment known in the art can be used. Base support  44  is made of a non-pliable material that provides structural support for pad base  45  and also a means for pad bolt  46  to be tightened to spindle  36 . Pad base  45  is made of a pliable material that will provide for a dampened interface between a work surface and the user. Preferably, base support  44  is made from plastic and pad base  45  is a high density foam or similar rubber, but it should be appreciated that any similar materials could be used for either base support  44  or pad base  45 . Base support  44  is attached to spindle  36  by means of pad bolt  46 . Pad bolt  46  is recessed within pad base  45  and is most clearly shown in  FIG. 4 . 
   Referring back to  FIG. 2 , pad base  45  preferably comprises either a hook or loop surface. Alternatively, pad  48  comprises a loop or hook surface so that pad base  45  and pad  48  may be attached by a hook and loop interface. This allows for a quick and easy replacement of pad  48  or change exchanging pad  48  with an abrasive pad having different abrasive properties. 
   It should be appreciated that any type of pad  48  could be used. Pad  48  could be a piece of sand paper of any grit size. Alternatively, pad  48  could be a polishing pad, buffing pad, or any other pad known in the art. 
   Thus, it is seen that the objects of the present invention are efficiently obtained, although modifications and changes to the invention should be readily apparent to those having ordinary skill in the art, which modifications are intended to be within the spirit and scope of the invention as claimed. It also is understood that the foregoing description is illustrative of the present invention and should not be considered as limiting. Therefore, other embodiments of the present invention are possible without departing from the spirit and scope of the present invention.