Abstract:
A coupling apparatus includes an inner shaft rotatably driven about a longitudinal axis of rotation, an outer shaft concentric with the inner shaft for selective rotation about the longitudinal axis, a coupling element movable between a first position engaging the inner shaft to the outer shaft for rotation therewith, and a second position disengaging the inner shaft from the outer shaft for relative rotation therebetween, and an actuating element connected to the coupling element and operable to move the coupling element between the first position and the second position.

Description:
BACKGROUND OF THE INVENTION 
   This invention relates generally to washing machines and, more specifically, to a mechanism for coupling and de-coupling appropriate elements of a washing machine during selected portions of the wash cycle. 
   At least some known washing machines typically include a perforated basket for holding clothing or other articles to be washed, an agitator disposed within the basket which agitates the clothes in the basket, and a motor which drives the agitator and the basket. The articles to be washed are immersed in water with detergent and washed under the influence of an oscillating agitator. After agitation, the articles are rinsed with clean water and the basket is spun at sufficient speed to centrifugally extract the rinse water from the articles. 
   Generally, the agitator and basket are mounted on concentric shafts with the agitator shaft internal to the basket shaft. During agitation, the basket and basket shaft are motionless while the agitator shaft and agitator are free to oscillate to impart a cleaning action to the articles being washed. During spin cycles, the agitator shaft and basket shaft are engaged so that the agitator and basket spin in concert with no relative motion between the two. The coupling and uncoupling of the agitator and basket shafts is usually controlled by the mechanical drive system. However, the drive system could be simpler and less costly to manufacture if the coupling of the basket and agitator was controlled by a separate system. 
   BRIEF DESCRIPTION OF THE INVENTION 
   In one aspect, a coupling apparatus includes an inner shaft rotatably driven about a longitudinal axis of rotation, an outer shaft concentric with the inner shaft for selective rotation about the longitudinal axis, a coupling element movable between a first position engaging the inner shaft to the outer shaft for rotation therewith, and a second position disengaging the inner shaft from the outer shaft for relative rotation therebetween, and an actuating element connected to the coupling element and operable to move the coupling element between the first position and the second position. 
   In another aspect, a washing machine includes a wash tub, a perforated basket rotatably mounted within the tub, an agitation element disposed within the basket to agitate articles, an outer shaft connected to the basket to drive the basket, an inner shaft connected to the agitation element to drive the agitation element, a motor drivingly connected to the inner shaft, and a coupling mechanism to selectively couple the inner shaft and the outer shaft. 
   In another aspect, a method of coupling and de-coupling a shaft driven agitation element and basket in a washing machine, the agitation element being driven by an inner shaft and the basket being driven by an outer shaft, includes disposing the inner shaft within the outer shaft so that the inner and outer shafts share a common axis of rotation, providing a coupling element concentric with the inner and outer shafts movable between a first position engaging the outer shaft with the inner shaft for rotation therewith and a second position disengaging the shafts for relative motion therebetween, driving the inner shaft, and moving the coupling element between the first and second positions based on a portion of a wash cycle. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view partially broken away of an exemplary washing machine. 
       FIG. 2  is front elevational schematic view of the washing machine shown in  FIG. 1 . 
       FIG. 3  is a left half cross sectional view of one embodiment of a coupling and de-coupling mechanism with the coupling disengaged. 
       FIG. 4  is a right half cross sectional view of the coupling of  FIG. 3  with the coupling engaged. 
       FIG. 5  is a left half cross sectional view of another embodiment of a coupling and de-coupling mechanism with the coupling disengaged. 
       FIG. 6  is a right half cross sectional view of the coupling of  FIG. 5  with the coupling engaged. 
       FIG. 7  is a left half cross sectional view of another embodiment of a coupling and de-coupling mechanism with the coupling disengaged. 
       FIG. 8  is a right half cross sectional view of the coupling of  FIG. 7  with the coupling engaged. 
       FIG. 9  is a left half cross sectional view of yet another embodiment of a coupling and de-coupling mechanism with the coupling disengaged. 
       FIG. 10  is a right half cross sectional view of the coupling of  FIG. 9  with the coupling engaged. 
       FIG. 11  is a cross sectional view of another embodiment of a coupling and de-coupling mechanism. 
       FIG. 12  is a left half cross sectional view of another embodiment of a coupling and de-coupling mechanism with the coupling disengaged. 
       FIG. 13  is a right half cross sectional view of the coupling of  FIG. 12  with the coupling engaged. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  is a perspective view partially broken away of an exemplary washing machine  50  including a cabinet  52  and a cover  54 . A backsplash  56  extends from cover  54 , and a control panel  58  including a plurality of input selectors  60  is coupled to backsplash  56 . Control panel  58  and input selectors  60  collectively form a user interface input for operator selection of machine cycles and features, and in one embodiment, a display  61  indicates selected features, a countdown timer, and other items of interest to machine users. A lid  62  is mounted to cover  54  and is rotatable about a hinge (not shown) between an open position (not shown) facilitating access to a wash tub  64  located within cabinet  52 , and a closed position (shown in  FIG. 1 ) forming an enclosure over wash tub  64 . As illustrated in  FIG. 1 , machine  50  is a vertical axis washing machine. 
   Tub  64  includes a bottom wall  66  and a sidewall  68 , and a basket  70  is rotatably mounted within wash tub  64 . A pump assembly  72  is located beneath tub  64  and basket  70  for gravity assisted flow when draining tub  64 . Pump assembly  72  includes a pump  74  and a motor  76 . A pump inlet hose  80  extends from a wash tub outlet  82  in tub bottom wall  66  to a pump inlet  84 , and a pump outlet hose  86  extends from a pump outlet  88  to an appliance washing machine water outlet  90  and ultimately to a building plumbing system discharge line (not shown) in flow communication with outlet  90 . 
     FIG. 2  is a front elevational schematic view of washing machine  50  including wash basket  70  movably disposed and rotatably mounted in wash tub  64  in a spaced apart relationship from tub side wall  64  and tub bottom  66 . Basket  70  includes a plurality of perforations therein to facilitate fluid communication between an interior of basket  70  and wash tub  64 . 
   A hot liquid valve  102  and a cold liquid valve  104  deliver fluid, such as water, to basket  70  and wash tub  64  through a respective hot liquid hose  106  and a cold liquid hose  108 . Liquid valves  102 ,  104  and liquid hoses  106 ,  108  together form a liquid supply connection for washing machine  50  and, when connected to a building plumbing system (not shown), provide a fresh water supply for use in washing machine  50 . Liquid valves  102 ,  104  and liquid hoses  106 ,  108  are connected to a basket inlet tube  110 , and fluid is dispersed from inlet tube  110  through a known nozzle assembly  112  having a number of openings therein to direct washing liquid into basket  70  at a given trajectory and velocity. A dispenser (not shown in  FIG. 2 ), may also be provided to produce a wash solution by mixing fresh water with a known detergent or other composition for cleansing of articles in basket  70 . 
   In an alternative embodiment, a spray fill conduit  114  (shown in phantom in  FIG. 2 ) may be employed in lieu of nozzle assembly  112 . Along the length of the spray fill conduit  114  are a plurality of openings arranged in a predetermined pattern to direct incoming streams of water in a downward tangential manner towards articles in basket  70 . The openings in spray fill conduit  114  are located a predetermined distance apart from one another to produce an overlapping coverage of liquid streams into basket  70 . Articles in basket  70  may therefore be uniformly wetted even when basket  70  is maintained in a stationary position. 
   An agitation element  116 , such as a vane agitator, impeller, auger, nutator, infuser, or oscillatory basket mechanism, or some combination thereof is disposed in basket  70  to impart an oscillatory motion to articles and liquid in basket  70 . 
   A wash cycle generally includes one or more agitation cycles alternated with one or more spin cycles. During agitation, agitation element  116  oscillates imparting a cleaning action to items being washed. During agitation, basket  70  is stationary. During the spin cycles, agitation element  116  and basket  70  rotate together with no relative motion therebetween. 
     FIG. 3  illustrates a left half cross sectional view of one embodiment of a coupling and de-coupling mechanism  400  to control the relative movements of agitation element  116  and basket  70  of washing machine  50 . In  FIG. 3 , coupling mechanism  400  is disengaged.  FIG. 4  illustrates a right half cross sectional view of the coupling and de-coupling mechanism of  FIG. 3 , where the coupling is engaged. Coupling and de-coupling mechanism  400  operates on inner shaft  410  and an outer shaft  420 . Inner shaft  410  is internal to and concentric with outer shaft  420 . Inner shaft  410  is connected to and driven by a rotor  440 . Rotor  440  includes a central recessed portion  442  that receives a cylindrical coupler  430 . Coupler  430  includes a lower portion  432  including a plurality of first splines  434  configured to engage a plurality of external splines  412  on inner shaft  410 . Coupler  430  is free to slide along inner shaft external splines  412 . Coupler  430  includes an upper portion  438  that includes a plurality of second splines  436  configured to engage a plurality of external splines  424  on outer shaft  420 . An actuator  450  moves coupler  430  along inner shaft external splines  412 . 
   Coupler  430  moves up and down inner shaft external splines  412  to engage and disengage inner shaft  410  with outer shaft  420 . During agitation, inner shaft  410  and outer shaft  420  are disengaged as shown in  FIG. 3 . In  FIG. 4 , coupler  430  rests in recess  442  of rotor  440  so that second splines  436  on coupler upper portion  438  are not engaged with external splines  424  on outer shaft  420 . Inner shaft  410  is thus free to move relative to outer shaft  420 . During spin cycles, actuator  450  moves coupler  430  upward along inner shaft  410  to engage external splines  424  on outer shaft  420  as illustrated in  FIG. 4 . In this position, inner shaft  410  and outer shaft  420  are engaged so that outer shaft  420  is driven by inner shaft  410  for simultaneous rotation during the spin cycle. In one embodiment, actuator  450  is a solenoid that is controlled by a controller coupled to control panel  58 . In alternative embodiments, actuator  450  includes an electric motor, a spring, or a wax motor. 
   In the embodiments of  FIGS. 3 and 4 , the mating geometry between the coupling and shaft members is only in the shaft members with no special rotor bushing or boss design required to mesh the coupler in the engaged or disengaged positions. This allows the coupler to be designed to occupy a smaller space. 
     FIG. 5  illustrates a left half cross sectional view of another embodiment of a coupling and de-coupling mechanism  500  to control the relative movements of agitation element  116  and basket  70  of washing machine  50 . In  FIG. 5 , coupling mechanism  500  is disengaged.  FIG. 6  illustrates a right half cross sectional view of the coupling and de-coupling mechanism of  FIG. 5 , where the coupling is engaged. Coupling and de-coupling mechanism  500  operates on inner shaft  510  and a outer shaft  520 . Inner shaft  510  is internal to and concentric with outer shaft  520 . Inner shaft  510  is connected to and driven by a rotor  540 . A coupler  530  includes a lower portion  532  and an upper portion  538 . Coupler  530  is concentric with inner shaft  510  and outer shaft  520 . Upper portion  538  of coupler  530  includes a plurality of internal splines  534  configured to engage a plurality of external splines  512  on inner shaft  510 . Upper portion  538  of coupler  530  includes a plurality of external splines  536  configured to engage a plurality of internal splines  524  on outer shaft  520 . Coupler  530  is free to slide along inner shaft splines  512 . An actuator  550  moves coupler  530  downward along inner shaft  510  on splines  512 . A biasing member  560  biases coupler  530  in an upward position. In one embodiment, biasing member  560  is a spring. 
   Coupler  530  moves up and down inner shaft splines  512  to engage and disengage inner shaft  510  with outer shaft  520 . During agitation, inner shaft  510  and outer shaft  520  are disengaged as shown in  FIG. 5 . In  FIG. 5 , coupler  530  is held in a downward position under the influence of actuator  550  against biasing member  560 . In this position, splines  536  on coupler upper portion  538  are not engaged with splines  524  on outer shaft  520 . Inner shaft  510  is thus free to move relative to outer shaft  520 . During spin cycles, actuator  550  is pivoted upward allowing biasing member  560  to force coupler  530  upward along inner shaft  510  to engage splines  524  on outer shaft  520  as illustrated in  FIG. 6 . In this position, inner shaft  510  and outer shaft  520  are engaged so that outer shaft  520  is driven by inner shaft  510  for simultaneous rotation during the spin cycle. 
   In the embodiments of  FIGS. 5 and 6 , the mating geometry between the coupling and shaft members is only in the shaft members with no special rotor bushing or boss design required to mesh the coupler in the engaged or disengaged positions. This allows the coupler to be designed to occupy a smaller space. In addition, the transfer of torque from the internal member between the shafts takes place in the same plane, effectively decreasing coupler flexure. 
     FIG. 7  illustrates a left half cross sectional view of another embodiment of a coupling and de-coupling mechanism  600  to control the relative movements of agitation element  116  and basket  70  of washing machine  50 . In  FIG. 7 , coupling mechanism  600  is disengaged.  FIG. 8  illustrates a right half cross sectional view of the coupling and de-coupling mechanism of  FIG. 7 , where the coupling is engaged. Coupling and de-coupling mechanism  600  operates on inner shaft  610  and a outer shaft  620 . Inner shaft  610  is internal to and concentric with outer shaft  620 . Inner shaft  610  is connected to and driven by a rotor  640 . A cylindrical coupler  630  includes a lower portion  632 , an upright portion  638 , and a locking arm  639  extending radially outward from upright portion  638 . In one embodiment, coupler  630  includes at least two locking arms  639  to facilitate balancing of the mechanism. Locking arm  639  includes a locking notch  637 . Coupler  630  is concentric with inner shaft  610  and outer shaft  620 . Upright portion  638  of coupler  630  includes a plurality of internal splines  636  at an upper end thereof. Splines  636  are configured to engage a plurality of external splines  624  on outer shaft  620 . Lower portion  632  of coupler  630  includes a plurality of internal splines  634  configured to engage a plurality of external splines  612  on inner shaft  610 . Coupler  630  is free to slide along outer shaft splines  624 . Rotor  640  includes a central recessed portion  642  that receives lower portion  632  of coupler  630  when coupler  630  is at the lower end of its travel. Inner shaft  610  includes a spline free section  614  adjacent rotor recess  642  such that coupler  630  is disengaged from inner shaft  610  when coupler  630  is seated in rotor recess  642 . A coupler plate  672  is connected to the washer tub  670  and includes an arm  674  that includes a locking member  676 . Locking member  676  is configured to be received in locking notch  637  of locking arm  639 . A biasing member  660  is positioned between tub  670  and locking arm  639 . Biasing member  660  operates to bias coupler  630  toward rotor recess  642 . In one embodiment, biasing member  660  is a spring. 
   Coupler  630  moves up and down outer shaft splines  624  to engage and disengage inner shaft  610  with outer shaft  620 . During agitation, inner shaft  610  and outer shaft  620  are disengaged as shown in  FIG. 7 . In  FIG. 7 , coupler  630  is held in a downward position by biasing member  660 . In this position, splines  634  on coupler lower portion  632  are not engaged with splines  612  on inner shaft  610 . Inner shaft  610  is thus free to move relative to outer shaft  620  while locking member  676  is received in locking notch  637  to hold outer shaft  620  stationary. During spin cycles, an actuator (not shown in  FIGS. 7 and 8 ) moves coupler  630  upward against biasing member  660  so that splines  634  on coupler  630  engage splines  612  on inner shaft  610  as illustrated in  FIG. 8 . In this position, inner shaft  610  and outer shaft  620  are engaged so that outer shaft  620  is driven by inner shaft  610  for simultaneous rotation during the spin cycle. In another embodiment, inner shaft  610  is configured with splines  612  and spline free section  614  switched, positioning splines  612  adjacent rotor recess  642  and the relative positions of coupling arm  674  and locking arm  639  are reversed so that the agitate and spin positions of coupler  630  are reversed. That is, agitation occurs when coupler  630  is elevated and spin occurs when coupler  630  is lowered. 
   In the embodiments of  FIGS. 7 and 8 , the mating geometry between the coupling and shaft members is only in the shaft members with no special rotor bushing or boss design required to mesh the coupler in the engaged or disengaged positions. Rotation of one shaft is inhibited while the other shaft is mobilized. 
     FIG. 9  illustrates a left half cross sectional view of yet another embodiment of a coupling and de-coupling mechanism  700  to control the relative movements of agitation element  116  and basket  70  of washing machine  50 . In  FIG. 9 , coupling mechanism  700  is disengaged.  FIG. 10  illustrates a right half cross sectional view of the coupling and de-coupling mechanism of  FIG. 9 , where the coupling is engaged. Coupling and de-coupling mechanism  700  operates on inner shaft  710  and a outer shaft  720 . Inner shaft  710  is internal to and concentric with outer shaft  720 . Inner shaft  710  is connected to and driven by a rotor  740 . A cylindrical coupler  730  includes a lower portion  732  including a plurality of splines  734  configured to engaged a plurality of external splines  712  on inner shaft  710 . Coupler  730  is free to slide along inner shaft splines  712 . Coupler  730  includes an upwardly projecting rim  738  that includes teeth  736 . A hub  726  is attached to the lower end of outer shaft  720  and includes a flange  728  that includes a downwardly facing channel  718  that includes teeth  722  configured for engagement with teeth  736  on coupler rim  738 . An actuator (not shown in  FIGS. 9 and 10 ) moves coupler  730  along inner shaft splines  712 . 
   Coupler  730  moves up and down inner shaft splines  712  to engage and disengage inner shaft  710  with outer shaft  720 . During agitation, inner shaft  710  and outer shaft  720  are disengaged as shown in  FIG. 9 . In  FIG. 9 , coupler  730  is moved downward on inner shaft  710  so that teeth  736  on coupler rim  738  are not engaged with teeth  722  on flange  728 . Inner shaft  710  is thus free to move relative to outer shaft  720 . During spin cycles, coupler  730  is moved upward along inner shaft splines  712  so that coupler rim teeth  736  engage teeth  722  on flange  728  as illustrated in  FIG. 10 . In this position, inner shaft  710  and outer shaft  720  are engaged so that outer shaft  720  is driven by inner shaft  710  through hub  726  for simultaneous rotation during the spin cycle. 
   In the embodiments of  FIGS. 9 and 10 , spline-to-spline misalignment failure during the coupling process is reduced. In addition, there is a lower force on the coupler geometry due to the larger radial interface point of mating. 
   In another embodiment, a coupling and de-coupling mechanism  800  to control the relative movements of agitation element  116  and basket  70  of washing machine  50  is illustrated in  FIG. 11 . Coupling and de-coupling mechanism  800  operates on an inner shaft  810  and a outer shaft  820 . Inner shaft  810  is internal to and concentric with outer shaft  820 . Inner shaft  810  is connected to and driven by a rotor  840 . Inner shaft  810  includes a plurality of external splines  812  around a lower portion thereof. A magnetic fluid  850  fills the lower portion of a space  852  between inner shaft  810  and outer shaft  820 . A seal  854  seals the lower end of space  852  to retain fluid  850 . An electromagnet  830  at the base of inner shaft  810  is energized or de-energized to control the viscosity of magnetic fluid  850 . 
   During agitation, electromagnet  830  is not energized. When electromagnet  830  is not energized, the viscosity of magnetic fluid  850  is sufficiently low that splines  812  of inner shaft  810  do not grip magnetic fluid  850  so that relative motion between inner shaft  810  and outer shaft  820  takes place. During spin cycles, electromagnet  830  is energized increasing the viscosity of magnetic fluid  850  such that splines  812  grip magnetic fluid  850  so that inner shaft  810  and outer shaft  820  both rotate. 
   The embodiments of  FIG. 11  do not entail the use of levers or mechanical actuating devices while offering variable coupling force and space savings. 
     FIG. 12  illustrates a left half cross sectional view of another embodiment of a coupling and de-coupling mechanism  900  to control the relative movements of agitation element  116  and basket  70  of washing machine  50 . In  FIG. 12 , coupling mechanism  900  is disengaged.  FIG. 13  illustrates a right half cross sectional view of the coupling and de-coupling mechanism of  FIG. 12 , where coupling mechanism  900  is engaged. Coupling and de-coupling mechanism  900  operates on inner shaft  910  and a outer shaft  920 . Inner shaft  910  is internal to and concentric with outer shaft  920 . Inner shaft  910  is connected to and driven by a rotor  940 . A cylindrical coupler  930  includes a lower portion  932 , an upright portion  938 , and a locking flange  939  extending radially outward from upright portion  938 . Locking flange  939  includes an upwardly extending locking rim  937 . Coupler  930  is concentric with inner shaft  910  and outer shaft  920 . Upright portion  938  of coupler  930  includes a plurality of internal splines  936  at an upper end thereof. Splines  936  are configured to engage a plurality of external splines  924  on outer shaft  920 . Lower portion  932  of coupler  930  includes a plurality of internal splines  934  configured to engage a plurality of external splines  912  on inner shaft  910 . Coupler  930  is free to slide along outer shaft splines  924 . Rotor  940  includes a central recessed portion  942  that receives lower portion  932  of coupler  930  when coupler  930  is at the lower end of its travel. Inner shaft  910  includes a spline free section  914  adjacent rotor recess  942  such that coupler  930  is disengaged from inner shaft  910  when coupler  930  is seated in rotor recess  942 . A number of locking pawls  976  are pivotably attached to washer tub  970  through a plurality of pivot pins  972 . Locking rim  937  is configured to engage an outer edge of locking pawls  976 . Biasing member  960  is positioned between tub  970  and locking pawls  976 . Biasing member  960  operates to bias locking pawls  976  into engagement with outer shaft  920  holding outer shaft  920  stationary. In one embodiment, biasing member  960  is a spring. 
   Coupler  930  moves up and down outer shaft splines  924  to engage and disengage inner shaft  910  with outer shaft  920 . During agitation, inner shaft  910  and outer shaft  920  are disengaged as shown in  FIG. 12 . In  FIG. 12 , an actuator (not shown in  FIGS. 12 and 13 ) moves coupler  930  to a downward position with coupler lower portion  932  within rotor recess  942 . In this position, splines  934  on coupler lower portion  932  are not engaged with splines  912  on inner shaft  910 . Inner shaft  910  is thus free to move relative to outer shaft  920 . Locking pawls  976  are engaged with outer shaft  920  to hold outer shaft  920  stationary. During spin cycles, an actuator (not shown in  FIGS. 12 and 13 ) moves coupler  930  upward against biasing member  960  so that splines  934  on coupler  930  engage splines  912  on inner shaft  910  as illustrated in  FIG. 13 . In this position, inner shaft  910  and outer shaft  920  are engaged so that outer shaft  920  is driven by inner shaft  910  for simultaneous rotation during the spin cycle. Locking rim  937  engages locking pawls  976  urging pawls  976  to pivot downward freeing outer shaft  920  for rotation. 
   In the embodiments of  FIGS. 12 and 13 , the mating geometry between the coupling and shaft members is only in the shaft members with no special rotor bushing or boss design required to mesh the coupler in the engaged or disengaged positions. Rotation of one shaft is inhibited while the other shaft is mobilized. 
   While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.