Abrading – Frame or mount – Portable abrader
Reexamination Certificate
2000-05-16
2001-10-23
Hail, III, Joseph J. (Department: 3723)
Abrading
Frame or mount
Portable abrader
C451S358000, C451S359000
Reexamination Certificate
active
06306024
ABSTRACT:
TECHNICAL FIELD
This application relates to orbital tools and to center pivot mechanisms for use in orbital tools.
BACKGROUND ART
The use of orbital tools has become widespread. For example, detail sanders having orbital sanding heads are used for performing specific finishing tasks such as sanding edges adjacent internal walls. To perform such tasks, the tools utilized must have controlled finite movement in a confined area so as to fine sand the desired area without damaging the surface upon which the work is being performed. Various approaches have been taken to perform the difficult task of sanding these internal corners and other hard to reach areas which require fine sanding or abrasion. Further, there are other applications for orbital tools, such as rough wood working sanders and auto body sanders.
Orbital tools utilize center pivot mechanisms to orbit or vibrate the working member of the tool. Some of these orbital tools, such as detail sanders, employ constrained pivoting mechanisms which prevent the working member of the orbital tool from freely rotating relative to the housing. Others of these orbital tools, such as rough wood working and auto body sanders, employ random pivoting mechanisms which permit the working member to freely rotate relative to the housing.
One example of an orbital tool is described in U.S. Pat. No. 4,744,177 issued to Braun et al. The Braun et al. patent describes an orbital tool with a center pivot mechanism that changes the eccentricity of the working member axis, or the working offset, by reversing motor direction to rotate an intermediate member 180 degrees relative to the drive shaft about a drive shaft eccentric axis. The 180 degree rotation moves the working member axis to a different working offset on the other side of the drive shaft central axis.
A disadvantage associated with existing orbital tools is the fact that dust, dirt, and other debris often find their way into the center pivot mechanism, causing poor performance and premature wear. Another disadvantage is that existing pivot mechanisms do not allow a single orbital tool to have a variety of different working members, in addition to adjustable eccentricity. Yet another disadvantage associated with existing orbital tools, including those with adjustable eccentricity mechanisms, is that a high moment of inertia about the eccentric axis due to the intermediate and working members causes excessive component loading and wear, particularly during motor reversing.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an orbital tool having an improved center pivot mechanism.
It is another object of the present invention to provide an improved orbital tool in which the working member may be selected from a plurality of working members to provide different types of working member pivotal movement as desired, such as constrained pivoting, controlled pivoting or random pivoting.
It is a further object of the present invention to provide an improved adjustable eccentricity orbital tool in which the center pivot mechanism is adjustable to vary the working member offset from the drive axis, while having a reduced moment of inertia about the eccentric axis due to the intermediate and working members to reduce component loading and wear.
In carrying out the above objects and other objects and features of the present invention, an orbital tool is provided. The orbital tool comprises a motor oriented within a housing, and an eccentric drive member pivotally supported relative to the housing and rotatably driven by a motor shaft. The motor shaft rotatably drives the eccentric drive member about a drive axis; and, the eccentric drive member has an output portion aligned along an eccentric axis. The eccentric axis is generally parallel to and radially offset from the drive axis.
A working member has an input portion, a mating surface, and a working surface. The working surface is perpendicular to the drive axis and extends radially outboard of the input portion. The working member input portion engages the output portion of the eccentric drive member, and is aligned along the eccentric axis to orbit about the drive axis as the drive member is rotated by the motor shaft.
An annular pivot control member has an annular central hub, an annular flange, and a web extending between the flange and the central hub. The central hub has a mating surface cooperating with the working member mating surface. The annular flange engages the housing at a location spaced from the central hub. The central hub mating surface and working member mating surface cooperate to control pivotal movement of the working member relative to the housing. The web enables the working member input portion to orbit about the drive axis as the eccentric drive member is rotated by the motor shaft.
In one embodiment, the central hub mating surface is affixed to the working member mating surface, and the flange is attached to the housing. The web prevents the working member from freely rotating relative to the housing, while elastically deforming sufficiently to enable the working member input portion to orbit the drive axis as the eccentric drive member is rotated by the motor shaft.
Further in carrying out the present invention, an orbital tool having a housing, motor, eccentric drive member, pivot control member, and a working member selected from a plurality of working members is provided. A first working member of the plurality of working members has a mating surface configured to mate with the central hub mating surface. The mating surfaces substantially prevent pivotal movement of the first working member relative to the housing as the eccentric drive member is rotated by the motor shaft. A second working member of the plurality of working members has a smooth surface positioned against the central hub mating surface. The smooth surface has a sufficiently low coefficient of friction to allow pivotal movement of the second working member relative to the housing.
Preferably, the central hub mating surface is defined by a gear with circumferentially spaced teeth. A third working member has a mating surface defined by a gear having circumferentially spaced teeth about a larger circumference than a central hub gear circumference. The central hub gear teeth engage the third working member gear teeth to provide controlled rotation of the third working member relative to the housing, as the eccentric drive member is rotated by the motor shaft.
Still further in carrying out the present invention, an orbital tool having a housing, motor, eccentric drive member, intermediate drive member, and working member, is provided. The intermediate drive member is pivotally supported relative to the eccentric drive member. The intermediate drive member has an output portion aligned along a working axis generally parallel to and radially offset from the eccentric axis. A working offset is defined between the working axis and the drive axis. The intermediate drive member is selectively rotatable about the eccentric drive member to vary the working offset to provide an adjustable eccentricity orbital tool.
A first balance mass is positioned to rotate together with the intermediate drive member about the eccentric axis. The first balance mass is selected and positioned based in part on a first distance defined between the eccentric and working axes to substantially minimize the moments of mass about the eccentric axis due to the working member. A second balance mass is positioned to rotate together with the eccentric drive member about the drive axis. The second balance mass is selected and positioned based in part on a second distance defined between the drive and eccentric axes to substantially minimize the moments of mass about the drive axis due to the first balance mass and the working member. The first distance is less than the second distance to reduce the moment of inertia about the eccentric axis due to the first balance mass and the working member.
The advantages accruing to the present invention are numerous, for exam
Curcuri Jeremy J.
Fukinuki Masatoshi
Kai Nobuto
Nemazi John E.
Brooks & Kushman P.C.
Hail III Joseph J.
Ojini Anthony
One World Technologies Inc.
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