Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Determining balance or center of gravity
Reexamination Certificate
1997-11-19
2001-05-22
Louis-Jacques, Jacques H. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Determining balance or center of gravity
C700S279000, C324S207120, C324S207220, C324S207130, C074S468000, C074S469000, C073S573000
Reexamination Certificate
active
06236934
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a method and to an apparatus for balancing a spindle or other rotating machinery apparatus and, more particularly, to a method and apparatus for balancing a rotating spindle which is normally adapted to removably receive a tool.
Discussion
A typical machine tool assembly includes a rotating spindle or other type of elongated member which is normally adapted to selectively and removably receive a tool. Examples of such tools include lathes, milling machines, and other types of mechanical and/or electromagnetic devices. As the spindle rotates, the tool performs a certain predetermined operation.
Typically, these machine tool assemblies experience a certain amount of vibration caused by spindle and/or tool imbalance. Such vibrations or imbalance forces cause the tool to inaccurately perform the desired task and significantly decrease tool life. Such vibration forces increase as the algebraic square of the spindle rotational speed. New types of higher speed machine tool assemblies have experienced large and unacceptably high machining inaccuracies caused by this relatively large vibrational force.
Many attempts have been made to minimize such machine vibrations or imbalance forces by use of devices normally deployed upon the spindle and having manually adjusted weights or liquids which are adapted to be selectively moved in order to correct for these imbalances. While somewhat effective, these devices have been largely unacceptable since they require a relatively large amount of time to create the desired correction. This large time is required since each tool has a unique imbalance profile. Thus, each time a tool is changed a new balance adjustment must be made. Moreover, imbalance changes during the useful life of a single tool, requiring many adjustments even if the tool is changed or removed. If the correction time is relatively large, the “cycle time” or time interval needed to change and balance tools also become large and unacceptable.
There is therefore a need to provide a balancer apparatus which selectively corrects imbalance and thus corrects, reduces, and/or minimizes imbalance-induced vibration associated with rotating machine tool apparatuses including such apparatuses that rotate at relatively high speeds.
There is also a need to provide a balancer which corrects a relatively large amount of machine tool imbalance without detrimentally affecting cycle time and which may be employed in combination with lathes, milling machines, and other types of tooling apparatuses.
SUMMARY OF THE INVENTION
It is therefore a primary object of this invention to provide a method and apparatus for selectively and relatively quickly and efficiently balancing rotating machine apparatuses and similar types of devices.
It is another of this invention to provide a method and apparatus which corrects a relatively large amount of vibration which is caused by rotating imbalance.
It is yet a further object of this invention to provide a method and apparatus for machine tool balancing which corrects relatively large amounts of vibration without significantly increasing tool change or cycle time.
It is a further object of this invention to provide a balancer having only two moving parts or portions, thereby increasing the working life of a balancer and allowing for a relatively simple design which results in relatively and substantially low manufacturing and maintenance costs.
It is yet another object of this invention to provide a balancer which includes two balancing weights which are adapted to be selectively deployed and movable in general proximity to the apparatus to be balanced. Such movement, in the preferred embodiment of this invention, is accomplished by use of electromagnetically-induced forces.
It is another object of this invention to provide a balancing apparatus which is adapted to include an electromagnetic field generator in substantial non-contact communication with a movable weighted portion. Such an electromagnetic field, in the preferred embodiment of the invention, consists of pulses of alternating polarity recurring at relatively low frequencies. The fast rise time of the pulses, however, corresponds to substantially high frequency content.
It is yet a further object of this invention to provide a balancing apparatus which operates at a wide range of machine speeds, including relatively high speeds, and which has a rotation speed threshold that is substantially limited only by the strength of the materials which are used to construct the balancer.
It is a further object of this invention to provide a balancer having two unbalanced components which are adapted to be selectively moved in proximate relation to a rotation apparatus and which are further adapted to retain their position through the use of a plurality of permanent magnets even if power is not applied to the balancer or the machine accelerates at a relatively high rate magnitude.
It is yet another object of this invention to provide a balancer which is adapted to allow for storage of various balancing condition information such that these conditions may be easily duplicated.
Lastly, it is also an object of this invention to provide a balancer which is relatively thin and which has a moving portion devoid of electronic components which may fail at such high rotational speeds.
According to the teachings of one aspect of the present invention a balancer is provided. The balancer is comprised of:
(a) Rotation means coupled to a spindle; and
(b) Electromagnetic field generation means, in electromagnetic communication with said rotating means, for selectively moving a portion of said rotation means upon said spindle.
According to the teachings of a second aspect of the present invention a method of balancing a rotating machine is provided. The method compromises the steps of:
(a) Movably coupling a first member to said spindle;
(b) Placing two rotating members containing known unbalance and equipped with a plurality of permanent magnets in said first member;
(c) Electromagnetically communicating with said rotating members and permanent magnets, effective to move each rotating member independently to predetermined positions upon said rotating spindle.
Further objects, features, and advantages of the present invention will become apparent from a consideration of the following description and the appended claims when taken in conjunction with accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Various advantages of the present invention will become apparent to those skilled in the art by reading the following specification and by reference to the following drawings in which:
FIG. 1
is an isometric view of a balancer made in accordance with the teachings of the present invention;
FIG. 2
is an isometric view of a balancer made in accordance with the teachings of a second embodiment of this invention;
FIG. 3
is a side and partial cut-away view of the balancer shown in
FIG. 1
;
FIG. 4
is a side and partial cut-away view of the balancer shown in
FIG. 2
;
FIG. 5
is a diagrammatic view of the balancer rotors shown in
FIG. 3
illustrating the balancing methodology of the invention;
FIG. 6
is a front view of a rotor showing one possible configuration of weighted inserts which provide unbalance to the rotor;
FIG. 7
is a front view of a rotor showing one possible configuration of machined holes which provide unbalance to the rotor;
FIG. 8
is a front view of a ball bearing assembly mounted on the balancer rotating assembly and used to support the moveable rotors;
FIG. 9
is a diagrammatic representation of an initial neutral balancer configuration on an unbalanced machine;
FIG. 10
is a diagrammatic representation of how, after balancing, the rotor unbalances combine to correct machine unbalance;
FIG. 11
is a front view of a reticulated pole plate used in the balancer;
FIG. 12
is a front view of the balancer assembly showing the alignment of the rotor permanent magnets with the reticulated pole plate at a detent position of the rotor;
FIG. 13
is a partial cut-away v
Dyer Stephen William
Hackett Brian Kent
Kerlin Jack
Chupa & Alberti P.C.
Louis-Jacques Jacques H.
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