U.S. patent application number 11/220461 was filed with the patent office on 2006-01-12 for system and method for limiting vibration in an apparatus during a loss of power.
This patent application is currently assigned to LORD CORPORATION. Invention is credited to J. David Carlson, Michael J. Chrzan, Thomas Peuker, Lynn C. Yanyo.
Application Number | 20060006027 11/220461 |
Document ID | / |
Family ID | 27733035 |
Filed Date | 2006-01-12 |
United States Patent
Application |
20060006027 |
Kind Code |
A1 |
Carlson; J. David ; et
al. |
January 12, 2006 |
System and method for limiting vibration in an apparatus during a
loss of power
Abstract
An apparatus comprising a frame; a member movable relative to
said frame; a damping device interconnected between the frame and
the movable member; a controller for activating said damper to
generate a damping condition at a predetermined member operating
condition; and system for activating the damping device at a
predetermined operating condition of the moving member during a
loss of power to the apparatus. The damping device may comprise a
field controllable damper that includes a volume of field
controllable fluid, which may in turn comprise magnetorheological
fluid for example. The rheology of the field controllable fluid is
effected during the application of said field.
Inventors: |
Carlson; J. David; (Cary,
NC) ; Chrzan; Michael J.; (Apex, NC) ; Yanyo;
Lynn C.; (Cary, NC) ; Peuker; Thomas;
(Ammerthal, DE) |
Correspondence
Address: |
LORD CORPORATION;PATENT & LEGAL SERVICES
111 LORD DRIVE
CARY
NC
27512
US
|
Assignee: |
LORD CORPORATION
|
Family ID: |
27733035 |
Appl. No.: |
11/220461 |
Filed: |
September 7, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10079388 |
Feb 20, 2002 |
|
|
|
11220461 |
Sep 7, 2005 |
|
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Current U.S.
Class: |
188/267.2 ;
188/267 |
Current CPC
Class: |
F16F 2230/24 20130101;
F16F 9/535 20130101 |
Class at
Publication: |
188/267.2 ;
188/267 |
International
Class: |
F16F 15/03 20060101
F16F015/03 |
Claims
1. An apparatus, comprising: a) a frame; b) a member movable
relative to said frame; c) damping means including a volume of a
field controllable medium, the field controllable damper
interconnected between the frame and the movable member; d) a
controller for activating said field controllable damper to
generate a damping condition at a predetermined member operating
condition; and e) means for activating said damping means at a
predetermined operating condition of the moving member during a
loss of power to the apparatus.
2. The apparatus as claimed in claim 1 wherein the device is a
washing machine.
3. The apparatus as claimed in claim 2 wherein the device is a
front loading washing machine.
4. The apparatus as claimed in claim 2 wherein the device is a top
loading washing machine.
5. The apparatus as claimed in claim 1 wherein the device is a
centrifuge.
6. The apparatus as claimed in claim 1 wherein the field
controllable medium is a magnetorheological medium.
7. The apparatus as claimed in claim 6 wherein the
magnetorheological medium is a magnetorheological fluid.
8. The apparatus as claimed in claim 6 wherein the
magnetorheological medium is a magnetorheological powder
9. The apparatus as claimed in claim 1 wherein the damping means is
a piston-type damper.
10. The apparatus as claimed in claim 1 wherein said means for
activating said damping means during a loss of power to the
apparatus is comprised of a secondary controller and a storage
device, said secondary controller being in signal receiving
relation with the storage device.
11. The apparatus as claimed in claim 10 wherein said storage
device is comprised of at least one battery.
12. The apparatus as claimed in claim 10 wherein the storage device
is comprised of at least one capacitor.
13. The apparatus as claimed in claim 1 wherein said means for
activating said damping means during a loss of power to the
apparatus is comprised of a secondary controller and a means for
generating a signal for activating the secondary controller and
damping means, said secondary controller being in signal receiving
relation with the signal generating means and being in signal
transmitting relation with the damping means.
14. The apparatus as claimed in claim 13 wherein the signal
generating means is a storage device.
15. The apparatus as claimed in claim 14 wherein the storage device
is a battery.
16. The apparatus as claimed in claim 14 wherein the storage device
is a capacitor.
17. The apparatus as claimed in claim 13 wherein the signal
generating device is a generator.
18. The apparatus as claimed in claim 13 wherein the signal
generating device is a DC motor.
19. The apparatus as claimed in claim 13 wherein the signal
generating device is comprised of a magnet mounted on the damper
and a coil proximate the coil.
20. An apparatus, comprising: a) a frame; b) a member movable
relative to said frame; c) damping means including a volume of a
field controllable medium, the field controllable damper
interconnected between the frame and the movable member; d) a
controller for activating said field controllable damper to
generate a damping condition at a predetermined member operating
condition; and e) a means for limiting vibration in said apparatus
during a loss of power to the apparatus.
21. The apparatus as claimed in claim 20 wherein the means for
limiting vibration is comprised of a brake.
22. (canceled)
23. (canceled)
24. (canceled)
25. The apparatus as claimed in claim 20 wherein said means for
limiting vibration is comprised of a secondary controller in signal
receiving relation with a storage device, said secondary controller
being in signal transmitting relation with said damping means.
26. The apparatus as claimed in claim 20 wherein said means for
limiting vibration is comprised of a secondary controller in signal
receiving relation with a DC motor, said secondary controller being
in signal transmitting relation with said damping means.
27. The apparatus as claimed in claim 20 wherein said means for
limiting vibration is comprised of a secondary controller in signal
receiving relation with a generator, said secondary controller
being in signal transmitting relation with said damping means.
28. The apparatus as claimed in claim 25 wherein the storage means
is a battery.
29. In an apparatus comprising a frame; a movable member; a damping
device including a volume of a field controllable medium, the field
controllable damper interconnected between the frame and the
movable member; a controller for activating said field controllable
damper to generate a damping condition at a predetermined member
operating condition; and means for activating the damping device at
a predetermined operating condition of the moving member, the
method comprising the steps of upon loss of power to the apparatus,
supplying an activating signal to the means for activating the
damping device and as required supplying activating signals to the
damping device to change the rheology of the field controllable
medium in the damping device.
30. The method of claim 29 further comprising the additional step
of sending a signal from the controller to the damper activating
means at predetermined intervals.
31. In an apparatus comprising a frame; a movable member; a damping
device interconnected between the frame and the movable member
where said damping device is activated in response to a signal; a
controller for supplying said signal to activate said damper to
generate a damping condition at a predetermined member operating
condition; and means for activating the damping device at a
predetermined operating condition of the moving member, the method
comprising the steps of upon loss of power to the apparatus,
supplying an activating signal to the means for activating the
damping device and as required supplying activating signals to the
damping device to provide the required damping to the
apparatus.
32. The method as claimed in claim 31 wherein the damper comprises
a field controllable damper comprising a volume of field
controllable material, the method comprising the further step of
changing the rheology of the field controllable medium in the
damping device when the signal is sent to the damping device.
33. An apparatus, comprising: a) a frame; b) a member movable
relative to said frame; c) damping means interconnected between the
frame and the movable member, said damping means for supplying
damping in response to an actuating signal; d) a controller for
actuating said damper to generate a damping condition at a
predetermined member operating condition; and e) means for limiting
vibration in said apparatus during a loss of power to the
apparatus.
34. The apparatus as claimed in claim 33 wherein the damping means
is a field controllable damper, said damping means comprising a
volume of a field controllable medium.
35. The apparatus as claimed in claim 34 wherein the field
controllable medium is magnetorheological fluid.
Description
FIELD OF THE INVENTION
[0001] The invention relates to an apparatus that includes a device
for providing the required damping, resistance and motion control
to the apparatus where the device is actuated by a signal, and more
specifically the invention relates to a system and method for
limiting vibration in an apparatus that employs a signal actuated
damper during a loss of power to the apparatus.
BACKGROUND OF THE INVENTION
[0002] One class of well-known dampers and shock-absorbers uses a
volume of hydraulic fluid as the working medium to create damping
forces to control or minimize shock and/or vibration. Typically,
the damping forces are generated by pressures resisting movement
between operative components of the damper or shock absorber.
[0003] Another class of devices employed to minimize shock and/or
vibration comprises devices that include a field controllable
material such as a magnetorheological (MR) medium which may
comprise MR fluid or MR powder. Such devices referred to as "MR
devices" may be of the "rotary-acting" or "linear-acting" variety.
Known MR devices include linear dampers, rotary brakes, and rotary
clutches for example. Each MR device employs an MR medium comprised
generally of soft-magnetic particles dispersed within a carrier.
Typical particles include carbonyl iron, and the like, having
various shapes, but which are preferably spherical and have mean
diameters of between about 0.1 .mu.m to about 500 .mu.m. The
carrier is most frequently a fluid among the group of fluids
including low viscosity hydraulic oils, and the like. In operation,
these MR fluids exhibit a thickening behavior (a rheology change)
upon being exposed to a magnetic field. The higher the magnetic
field strength in the fluid, the higher the damping/restraining
force or torque that can be achieved within the MR device. The
magnetic field is generated by supplying a current to a coil that
is located proximate a pole piece
[0004] FIG. 1 illustrates an exemplary MR damper of the type
disclosed in U.S. Pat. Nos. 6,151,930 and 5,284,330 commonly
assigned to the assignee of the present invention, Lord Corporation
of Erie, Pa. the disclosures of which are incorporated herein by
specific reference. Damper 10 may be used in a variety of
applications. For example, a plurality of dampers may be used to
support an engine on a vehicle frame or to suspend a drum in a
washing machine cabinet or housing. The damper 10 of FIG. 1
includes cylindrical housing 12 that defines housing chamber 14 and
piston member 16 disposed in the chamber and adapted to be
translated linearly along axis 17 through the housing chamber. An
attachment stem 28 is made integral with one end of the housing 12
in a conventional manner and the free end of the stem is in turn
fixed to a frame such as the frame of a machine or engine by a
conventional connection member such as a bolt for example.
[0005] The piston body 18 and the housing wall 20 are made of a
magnetically permeable material such as a soft magnetic steel for
example and the piston body and housing comprise pole pieces that
define the path of magnetic field 22 represented in dashed font in
FIG. 1. The piston body includes a piston rod 32 that is securedly
fixed to the piston, and the free end of the rod is in turn fixed
in a conventional manner proximate the member, device or system
that is the primary source of vibratory displacement such as an
engine or an enclosure for a washing machine drum for example.
[0006] In the exemplary MR damper 10 of FIG. 1, a volume of a field
controllable medium such as a magnetorheological medium is
contained in an absorbent matrix 30 which is wrapped around the
piston body 18. The absorbent matrix may include polyurethane foam
for example. In an alternate embodiment, illustrated in
incorporated by reference U.S. Pat. No. 5,284,330 the field
controllable material is not retained in an absorbent matrix. A
substantial portion of the housing chamber is filled with a volume
of the field controllable material and during operation the field
controllable material is displaced from one end of chamber 14 to
the opposite end of chamber 14 as it is entrained in a gap between
the piston body and housing wall during axial displacement of the
piston through the housing chamber.
[0007] A magnetic field generating means 24 in the form of a coil
is mounted on the piston body 18 to be movable with the piston as
it is reciprocatingly displaced axially through the housing 14. The
field generating means alters the rheology of the field responsive
medium in proportion to the strength of the field. Wires 26 connect
the coil comprising the field generating means to a controller, not
shown in FIG. 1. The controller is disclosed schematically in FIGS.
3a and 3b and the controller will be described in greater detail
hereinafter.
[0008] During operation of damper 10 the field controllable medium
becomes increasingly viscous with increasing field strength and
provides a shear force to resist relative movement between housing
and piston members 12 and 16. When the pole pieces are energized by
magnetic field 22 the controllable fluid changes rheology in the
matrix 30 located between the movable member 18 and the housing 12.
In use, the circumferentially extending coil 24 generates a
magnetic field 22 that acts on the pole pieces 18 and 20 and the
field controllable medium contained by the matrix 30. The coil
generates a magnetic field in response to the current supplied to
the coil 24 by the controller. The resistive force produced by
changing the field controllable medium's rheology can be varied by
changing the magnetic field strength which in turn is controlled by
the amount of current supplied to the field generating means 24 by
the controller.
[0009] When the damper is used to suspend washing machine drums
from the washing machine cabinet, the magnitude of damping supplied
is adjusted for the different washing cycles. Turning now to FIG. 2
which is a graph representing the transmitted washing machine
forces during the range of washing machine drum spin speeds, the
supplied damping is increased between points A and B on FIG. 2
which defines a the range of speeds that occur during machine
resonance. For example, the washing machine represented by
exemplary FIG. 2 experiences resonance as the drum passes through
the speed range between minimum and maximum spin speed limit points
A and B which may be 100 and 200 rpm for example. Resonance occurs
during periods of machine drum acceleration and deceleration when
the drum is spinning in the speed range between threshold points A
and B. The supplied damping is reduced outside the spin speed range
between points A and B.
[0010] The adjustable damping provided to washing machines by
damper 10 is a considerable improvement over the single constant
damping supplied by passive damping devices. If the damping was not
supplied through resonance as the washing machine rotated through
the speeds that produce a resonance condition, the produced
vibratory forces could cause the washing machine to "walk" from its
operating location. Also, the vibratory forces could damage the
machine.
[0011] During a loss of power to the washing machine or other
apparatus supported by one or more dampers 10, the required current
is not supplied to the field generating means 24 to control damper
10. As a result, the requisite damping forces can not be supplied
by damper 10 to control the vibration produced during resonance
experienced as the washing machine rotates through the spin speeds
between points A and B. Thus the washing machine passes through
resonance undamped which could cause the washing machine to vibrate
from its desired operating position and the machine could be
damaged.
[0012] The foregoing illustrates limitations known to exist in
present damping devices and methods. Thus, it is apparent that it
would be advantageous to provide an alternative system and method
whereby vibration is controlled in the event there is a loss of
power to an apparatus. Accordingly, a suitable alternative is
provided including features more fully disclosed hereinafter.
SUMMARY OF THE INVENTION
[0013] The present invention provides a method and system for
controlling vibration in an apparatus in the event there is a loss
of power to the apparatus. The invention relates to an apparatus
that includes a device for providing the required damping,
resistance and motion control to the apparatus where the device is
actuated by a signal, and more specifically the invention relates
to a system and method for limiting vibration in an apparatus that
employs a signal actuated damper during a loss of power to the
apparatus.
[0014] More specifically, the present invention comprises an
apparatus, that further comprises a frame; a member movable
relative to said frame; damping means including a volume of a field
controllable medium, the field controllable damper being
interconnected between the frame and the movable member; a
controller for activating said field controllable damper to
generate a damping condition at a predetermined member operating
condition; and means for limiting vibration in said apparatus
during a loss of power to the apparatus.
Although the means for limiting vibration is described as a field
controllable damper, it should be understood that the device for
limiting vibration may be any suitable damping device that is
actuated by an electrical signal.
[0015] The means for limiting vibration may comprise the
combination of a secondary controller and a storage device such as
a battery or capacitor. Alternatively the secondary controller may
be combined with a generator or a DC motor. The secondary
controller may also be combined with a magnet attached to the
damper and a coil where current is induced in the coil as the
magnet is displaced by the damper. In each combination the battery,
capacitor, generator, DC motor or magnet/coil produces the
supplemental power required to activate the secondary controller
and dampers as required as the apparatus spins down to thereby
limit vibration in the apparatus.
[0016] Also, the means for limiting vibration may comprise a brake
that is moved into engagement with the movable member when the
power is lost by the apparatus. Such a brake may include a biasing
member such as a spring for biasing a contact member toward the
movable member and a solenoid for maintaining the contact member
away from the movable member. During periods where power is being
supplied to the apparatus the solenoid is activated by the
controller to maintain the contact member away from the movable
member. When power is lost, the solenoid is deactivated and the
biasing member moves the contact member into braking engagement
with the movable member.
[0017] The above-mentioned and further features, advantages, and
characteristics of the present invention will become apparent from
the accompanying descriptions of the preferred embodiments and
attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The accompanying drawings which form a part of the
specification, illustrate several key embodiments of the present
invention. The drawings and description together, serve to fully
explain the invention.
[0019] FIG. 1 is a longitudinal cross-section of a controllable
linear damper.
[0020] FIG. 2 is a graph of transmitted forces from a washing
machine tub during a spin cycle.
[0021] FIG. 3a is a front sectional view of a front loading washing
machine including field controllable dampers and first and second
alternate embodiment means for limiting vibration during loss of
power to the washing machine.
[0022] FIG. 3b is a front sectional view of a front loading washing
machine including field controllable dampers and third, fourth and
fifth alternate embodiment means for limiting vibration during loss
of power to the washing machine.
[0023] FIG. 4 is a side sectional view of a top loading washing
machine including field controllable dampers with integrated
springs.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] Most generally, the present invention is a system and method
for limiting vibration in an apparatus during a loss of power. The
apparatus may include, but shall not be limited to a washing
machine for example. The device for limiting vibration in such
method and system may comprise any suitable vibration control
device that is actuated by a signal. The vibration control device
may further comprise a field controllable damper like damper 10
described hereinabove where vibration control is produced by
supplying a signal to the device to effect the rheology of the
volume of the field controllable medium housed in the damper. In
order to describe a preferred embodiments of the present invention,
as the description proceeds the system and method of the present
invention will include the field controllable damper 10
[0025] Referring to the drawing FIGS. 3a and 3b that disclose the
five preferred embodiments of the invention, it should be noted
that the first and second embodiments are illustrated schematically
on FIG. 3a and the third, fourth and fifth embodiments of the
invention are illustrated on FIG. 3b. Multiple embodiments of the
systems for limiting vibration in an apparatus when power is lost
are disclosed on the same drawing figures to limit the number of
figures included in the specification. The embodiments are specific
and discrete systems as disclosed in accordance with the following
description and moreover as identified and referred to separately
as systems 130a, 130b, 130c, 130d and 130e hereinafter.
[0026] Now referring to the drawings wherein like numerals denote
like items, FIG. 3a is a front sectional view of apparatus 100a
that comprises the system 102 of the present invention for
controlling the dampers 10a of apparatus 100a in the event
electrical power supply to apparatus 100a is lost. The first and
second embodiment systems for limiting vibration when power is lost
are identified in FIG. 3a as 130a and 130b respectively. For
purposes of describing the preferred embodiments of the invention,
the apparatus 100a is a front loading clothes washing machine.
However it should be understood that the apparatus may be any
electrically powered apparatus with damping that is controlled by
one or more field controllable dampers. More specifically, in
addition to the front loading clothes washing machine 100a the
apparatus may include top loading washing machine 100b shown in
sectional schematic view of FIG. 4 or a centrifuge (not shown). The
systems and methods for controlling vibration operate the same on
different apparatus so that as the description proceeds the
structure and functionality of the five alternate embodiment
systems will be described in use with the front loading machine
100a.
[0027] Returning now to the clothes washing machine illustrated in
FIGS. 3a and 3b, the washing machine 100a comprises a housing 102
that defines a chamber 104 with controllable dampers 10a, such as
those described in reference to FIG. 1, mounted in the apparatus
100a as components of the suspension and damping system. The field
controllable dampers associated with top loading machine 100b are
identified in FIG. 4 as 10b. The front loading machine 100a has a
horizontally-mounted drum 106 including a rotational portion 108
rotationally fixed and drivable relative to drum 106 by a
conventional motor 112 and belt 114 system. The motor may be any
conventional motor such as any AC or DC type electric motor. The
motor is supported in a conventional manner by the housing 102
using the required brackets or other suitable connection members
(not shown). The drum 106 (and rotational portion 108) are flexibly
suspended relative to a housing or cabinet 102 by flexible springs
116, such as coil springs for example. Dampers 10a, of the type
previously described hereinabove provide control of radial
vibrations of the drum 106.
[0028] The dampers 10 are connected to master controller 120 in
signal receiving relation to the controller. The controller 120,
which may be any suitable microprocessor based controller, is in
signal receiving relation with sensor 122 which may be a speed
sensor for monitoring the rotational velocity of drum 108 or an
accelerometer that monitors drum vibration. The sensor is fixedly
mounted on the housing drum 106, but may be fixed in any suitable
location. For example, alternatively, the accelerometer may be
fixed to the housing 102 to measure the housing vibration.
[0029] During use, when power is supplied continuously to the
washing machine 100a, and the drum 108 is spinning with a
rotational velocity or drum spin speed that is within a range of
speeds predetermined to coincide with a resonance condition in the
drum, (for example the range between points A and B in FIG. 2) a
damper activating signal, in the form of a current is sent from the
master controller 120 to the dampers 10a in the manner represented
schematically in FIG. 3a. The resonance condition typically occurs
during the machine spin cycle. The current signal sent by
controller 120 to the dampers changes the rheology of the field
controllable material. As the viscosity of the material is
increased the dampers 10a provide the damping required to absorb
the vibratory loads present during the resonance condition. At
predetermined intervals, the sensor 122 delivers signals indicating
the measured rotational velocity of the drum 108 to the master
controller 120 and the controller logic determines when the speed
of the drum is outside the resonance spin speed limits. When the
speed is outside of the spin speed range defined between points A
and B, the controller stops sending the current signal to the
dampers and the damping provided by dampers 10a is reduced.
[0030] The apparatus 100a also includes a first embodiment means
for limiting vibration in the apparatus 100a in the event that
there is a loss of power to the apparatus, and such first
embodiment means is designated generally at 130a in FIG. 3a. When
power is lost by the apparatus, the controller 120 also loses power
and cannot transmit signals to dampers 10a as required. The first
embodiment means 130a is comprised of a storage means such as a
battery or other storage cell 132 and a secondary controller 134.
The secondary controller controls the damping supplied by field
controllable dampers 10a during a loss of power to the apparatus
100a and the secondary controller may comprise any suitable
microprocessor based controller. As shown in FIG. 3a, the secondary
controller is electrically connected to the storage means in signal
receiving relation therewith. The secondary controller 134 is also
in signal receiving relation with main controller 120 and is in
signal transmitting relation with dampers 10a of apparatus
100a.
[0031] In use, the main controller 120 transmits a voltage signal
to the secondary controller at predetermined intervals to indicate
that power is being supplied to the apparatus. The signal may be a
5V or 12V signal for example. If during at least one interval the
signal is not transmitted to the secondary controller, the
secondary controller logic determines that the main power supply to
the apparatus has been lost. The secondary controller 134
immediately begins to draw power from the battery 132 to power up
controller 134. Signals are sent from sensor 122 through the
controller 120 to the secondary controller. After power is lost by
apparatus 100a the rotational speed of the drum naturally starts to
decrease. Assuming the rotational speed of the drum is above upper
limit B of FIG. 2 when the power is lost, when the sensed
rotational velocity of the drum reaches the predetermined upper
resonance limit, B, in FIG. 2 a current signal is sent from
secondary controller 134 to dampers 10a to provide the damping
required to offset the vibratory forces generated during the
resonance condition. In this way, if power is lost, the apparatus
100a will not be damaged and will not "walk" from it desired
operating location.
[0032] Once the speed of the drum is sensed to be below the spin
speed represented by point A in FIG. 2, the secondary controller
stops sending current signals to dampers 10a. Soon thereafter, the
drum 108 comes to a stop. If the drum is rotating at a speed that
is below resonance lower speed limit A when the power is lost, the
battery will continue to supply power to the secondary controller
134 and no signal will be sent to dampers 10. The battery may have
enough storage capacity to power the system 130a for a period of
about 5-10 seconds which is about the period required to rotate the
drum down to a stop from any operating spin speed.
[0033] If the motor 112 is a conventional direct current (DC) type
motor, the kinetic energy of the drum 108 is converted to
electrical energy by the DC motor and the electrical energy is
available at the terminals of the DC motor. In an alternate
embodiment of the invention identified at 130b in FIG. 3a, during
normal use of apparatus 100a the storage means 132 may receive a
charge from the motor 112. The storage means may be a battery or
conventional capacitor plate. Alternatively, the storage means may
be a bank of batteries or capacitor plates. The motor is
electrically connected to the main controller in signal
transmitting relation with the controller. The electrical
connection is represented in dashed font connection 136. In the
alternate embodiment means for controlling vibration during loss of
power 130b, the capacitor (or battery) is continuously charged
during operation of apparatus 100a. The storage device 132 receives
the charging signal from the main controller as represented
schematically in FIG. 3a.
[0034] When power is lost by the apparatus 100a, the secondary
controller 134 immediately begins to draw power from the storage
device 132. The capacitive energy is released to the controller 134
and dampers 10a as required in the manner previously described in
conjunction with first embodiment means 130a until the drum comes
to a stop.
[0035] Third, fourth and fifth embodiment means for activating
dampers 10 and fail safe controller 134 during a loss of power to
apparatus 100a are illustrated in FIG. 3b and are identified
generally as 130c, 130d and 130e respectively. In third embodiment
means 130c, a conventional generator 140 is located proximate
spinning drum 108 and is connected to the drum by a conventional
belt 142 and in this way, the kinetic energy of the drum is
converted to electrical energy by the generator as the drum
rotates.
[0036] Although the electrical generator means 140 is illustrated
in FIG. 3b as being located away from motor 112 and driven by
separate drive belt 142, it should be understood that the generator
may be mechanically connected to the rotating shaft 113 of motor
112 or to the motor drive belt 114.
[0037] In use, when the apparatus 100a loses power, as the drum 108
spins down, the generator continues to produce electrical power
that is supplied directly to the secondary controller 134. If
during the spin down the drum speed falls within the spin speed
range between points A and B of FIG. 2 the secondary controller
supplies current signals to dampers 10a. The generator continues to
produce electrical energy until the drum 108 stops rotating.
[0038] A fourth embodiment means for limiting vibration during a
power loss is identified at 130d in FIG. 3b. The fourth embodiment
means comprises an electromechanical brake. Shown schematically in
FIG. 3b, the brake comprises a contact member 150 with a contact
end 152 located proximate the movable drum 108. The brake comprises
a pair of spaced rigid plates 154a, 154b. Plate 154b is fixed and
plate 154a is movable linearly relative to plate 154b. The ends of
a conventional spring member 156 such as a coil spring are
connected to the plates and the spring member serves to bias the
plates apart. Solenoid member 158 has ends that are connected to
the plates 154a and 154b and the solenoid serves to overcome the
outward bias of spring member 156. During the supply of power to
apparatus 100a an activating signal, in the form of a voltage, is
sent to solenoid 158 from controller 120 and serves to maintain the
solenoid retracted. When the solenoid is retracted the braking end
152 of contact member 150 is out of contact with the drum.
[0039] When power is lost, the solenoid activating signal is
terminated, and as a result, the spring extends causing plate 154a
to move linearly away from plate 154b and thereby causing braking
member end 152 to be moved into braking contact with the rotating
drum. The contact between member 150 and drum 108 causes the drum
to decelerate to a stop quickly. Brake 130d of the fourth
embodiment means of the present invention is illustrated
schematically for purposes of describing a fourth preferred
embodiment of the invention however it should be understood that
the brake may assume a variety of configurations. In summary the
brake comprises a braking member and a means for maintaining the
member away from the rotating drum when power is supplied and for
causing the member to be moved into engagement with the drum when
power to the apparatus is lost.
[0040] The fifth embodiment means for limiting vibration during a
power loss is identified as 130e in FIG. 3b. The fifth embodiment
system utilizes damper motion to induce electric current in a coil
located proximate the damper. A conventional permanent magnet 160
is fixed to the exterior of the housing of dampers 10a to be
movable therewith. The coil of conductive wire 162 is located
proximate each magnet member and is stationary. As the damper is
displaced linearly the damper induces electric current in the coil
in a conventional manner well known to one skilled in the art. As
shown in FIG. 3b, each coil is located in signal transmitting
relation to the secondary controller 134.
[0041] When the power is supplied to apparatus 100, the current is
induced in coil 162 as the dampers 10 are displaced linearly to
offset vibration of drum 108. When the power is lost, the electric
current is released to drive the secondary controller. The dampers
10a are activated as required by current signals from the
controller 134.
[0042] While several embodiments including the preferred embodiment
of the present invention have been described in detail, various
modifications, alterations, changes, and adaptations to the
aforementioned may be made without departing from the spirit and
scope of the present invention defined in the appended claims. It
is intended that all such modifications, alterations, and changes
be considered part of the present invention.
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