Abstract:
A lid lock for a washing machine or the like employs a rapid bistable electromagnetic actuator that is released at a predetermined time interval after the cessation of a spin signal, the time interval being selected to allow the spin basket to coast to a stop prior to the lid being unlocked. Because the actuator is bistable, it can remain locked despite possible power failure during which the spin basket may still be coasting yet the driving circuitry stores reserved power to unlock the lid after a suitable time delay. These same components can provide protection against entrapment in which the lid closure activates the spin cycle and lock because of a previous initiation of the spin cycle signal. Here, for the spin cycle to be initiated, the spin cycle signal must occur after lid closure.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     BACKGROUND OF THE INVENTION 
     The present invention relates to clothes washing machines and the like and specifically to a lock assembly for preventing access to the spin basket of such a washer during the spin cycle. 
     During the spin cycle of a washing machine, water is removed from wet clothes centrifugally by spinning the clothes at high speed in a spin basket. In order to reduce the possibility of injury to the user, the user must be prevented from having access to the spin basket while the spin basket is in motion. 
     One way of protecting the user from access to the rotating spin basket uses a lid switch on the washing machine to detect an opening of the washing machine lid. When the lid is opened by more than a predetermined amount, the lid switch disconnects power from the motor driving the spin basket and activates a brake to bring the rapidly spinning spin basket to a halt. The brake, which is required because of the large rotational momentum of a loaded spin basket, adds significant expense in the manufacture of the washing machine. Systems using brakes may be impractical for future washing machines using higher speed spin cycles to remove greater amounts of water from the wet clothes. 
     A second way of protecting the user from access to the rotating spin basket uses an electrically actuated lock for the washing machine lid. The lock holds the lid in a closed position for the duration of the spin cycle and for a period after the spin cycle necessary for the spin basket to coast to a stop. The locking mechanism typically uses a thermally actuated element, such as a bi-metallic strip or a wax motor, to position a locking bolt into engagement with the washing machine lid; the bolt prevents the lid from opening. At the conclusion of the spin cycle, the thermally actuated element begins to cool and after a predetermined cooling period, retracts the locking bolt from the washing machine lid and allows the lid to be raised. 
     The intrinsic delay in the thermally actuated element (required by its need to cool) prevents the lock from being defeated simply by removing power to the washing machine yet in the event of power loss, the lock can be assured of opening on its own after the fixed period of time. 
     A disadvantage of the thermally actuated element is that it is hard to accurately control the period during which the lid will be locked, the time being affected both by manufacturing tolerance and variations in the temperature of the environment of the washing machine. Further, such a mechanism is difficult to integrate with more sophisticated locking logic, such as systems which operate to reduce the likelihood of child entrapment or misuse of the washing machine. What is needed is an electromechanical locking system that provides the benefits of the thermally actuated element without its disadvantages. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides an electromagnetic lid locking mechanism that can release the lid rapidly after a precise interval of time regardless of power failures and which is resistant to being defeated by unplugging the washing machine. The stopping of the spin basket is inferred from the passage of a time interval selected to be longer than a coasting period of the washing machine spin basket. The electromagnetic lid locking mechanism is stable in either the locked or unlocked position when power is removed and hence the lock cannot be defeated by removing power from the washing machine. The circuitry driving the electromagnetic lid locking mechanism monitors and stores electrical power to ensure that the lid may be unlocked at the conclusion of the spin cycle, even if power is lost, reducing the possibility of the lid remaining locked when power fails. The same components and circuitry may be used to provide at small additional cost, a “lock-out” of the spin cycle in situations where a child might intentionally or unintentionally enter the spin basket after the spin cycle has been initiated while the lid is open. 
     Specifically, the present invention provides a lid locking assembly having a bistable electromagnetic lid locking mechanism that in a locked state, holds the lid closed until an unlock signal is received and in an unlocked state allows the lid to be freely opened until a lock signal is received, where the unlock and lock signals are power applied to the electromagnetic lid locking mechanism and wherein, absent power applied to the electromagnetic lid locking mechanism, the electromagnetic lid locking mechanism remains in its last state of locked and unlocked. The lid locking assembly further includes a logic circuit having a timer and an energy storage capacitor to provide the unlock signal to the electromagnetic lid locking mechanism a predetermined period of time after the cessation of the washing machine&#39;s spin cycle signal, wherein the storage capacitor provides energy for the unlock signal in the event of loss of external power to the washing machine. 
     Thus, it is another object of the invention to reduce the possibility of the electromagnetic lid locking mechanism remaining in the locked state when power is removed from the washing machine. The energy used to lock the electromagnetic lid locking mechanism automatically charges a storage capacitor to provide power for the later unlock signal. 
     It is another object of the invention to provide an electromagnetic lid locking mechanism that responds rapidly to stopping of the spin basket but that cannot be defeated by disconnecting power from the washing machine. During a power failure or after an intentional unplugging of the washing machine, the electromagnetic lid locking mechanism will not automatically release while the spin basket is in motion. 
     The lid locking assembly may also include a lid switch providing a lid closed signal when the lid is closed. The logic circuitry may receive the lid closed signal and provide power to the motor only when the lid switch indicates that the lid was closed. 
     Thus, it is yet another object of the invention to reduce the chance of entrapment of a small child if the lid were to close on the child at a time after the spin cycle signal was generated by the machine controls. The present logic circuitry provides this additional feature with a cost effective small addition of parts. 
     The foregoing and other objects and advantages of the invention will appear in the following description. The description is that of a preferred embodiment which does not necessarily represent the full scope of the invention. The scope of the invention is described by the concluding claims. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     FIG. 1 is a perspective view of a top loading washing machine showing placement of the lid locking assembly of the present invention beneath the lid and a rotation sensor near the spin basket; 
     FIG. 2 is a simplified perspective view of the electromechanical elements of the lid locking assembly of the present invention showing a rotating locking bolt for engaging an eye on the washing machine lid, the locking bolt attached to rotate in tandem with a ward plate interacting with contacts and an electrically operated stop; 
     FIG. 3 is a fragmentary elevational view of the rotating locking bolt and ward plate of FIG. 2 in a first unlocked position allowing opening and closing of the washing machine lid; 
     FIG. 4 is a figure similar to that of FIG. 3 showing the rotating locking bolt and ward plate in a second locked position holding the washing machine lid closed; 
     FIG. 5 is a simplified schematic diagram of the logic circuitry used to control the washing machine of FIG.  1  and electromechanical elements of FIG. 2; 
     FIG. 6 is a detailed schematic diagram of the logic circuitry of FIG. 5; 
     FIG. 7 is a flow chart describing the operation of the logical circuitry of FIG. 5 when connected in a washing machine; 
     FIG. 8 is a detail view of an alternative embodiment of an electromagnet coil shown in FIGS. 2-4 using a donut shaped permanent magnet; 
     FIG. 9 is a simplified schematic diagram of an alternative of the logic circuit used to control the washing machine of FIG.  1  and electromechanical elements of FIG. 2 without a spin sensor; 
     FIG. 10 is a detailed schematic diagram of the logic circuitry of FIG. 9; 
     FIG. 11 is a flow chart describing the operation of the logical circuitry of FIG. 9 when connected in a washing machine. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to FIG. 1, a washing machine  10  includes a lid  12  hinged at a rear edge to open over a spin basket  14  into which wet clothes may be received. During a spin cycle timed by a timer  13  on a rear console of the washing machine  10 , the clothes in the spin basket  14  are to be spun about a vertical axis by a drive motor assembly  16  to centrifugally extract water from the clothes. 
     An outer surface of the spin basket  14  supports a magnet  18  which, when the spin basket  14  rotates, passes a sensor  20  attached to the stationary housing of the washing machine  10 . The sensor  20  may be a magnetic reed switch closing in response to the approach of the magnet  18  such as will occur periodically during rotation of the spin basket  14 . 
     In an alternative embodiment, the magnet  18  and sensor  20  are attached to components of the drive motor assembly  16  that move with respect to one another as the spin basket  14  rotates but that are not affected by any eccentricity in spin basket rotation. 
     An eye  22  extending downward from the front edge of the lid  12 , opposite the hinging edge, may be received by a latch assembly  24  when the lid  12  is in a closed position. 
     As will be described in detail below, the latch assembly  24  includes a locking bolt that may engage the eye  22  thereby locking the lid  12  in its closed position preventing access to the spin basket  14  by the user. The mechanism is similar to that described in U.S. Pat. No. 5,520,424 issued May 28, 1996 and entitled: “Tamper-Proof Door Switch and Latch Device” and hereby incorporated by reference. 
     Referring now generally to FIGS. 2 through 4, the latch assembly  24  includes a locking bolt  28  mounted to rotate generally about a horizontal axis  31  and having an upper tooth  30  that may engage the eye  22 . When the lid  12  is open, the locking bolt  28  is rotated so that the tooth  30  is tipped upward to allow the eye  22  to move downward past the tooth  30  unimpeded with a closing of the lid  12  as shown in FIG.  3 . When the lid  12  is closed, pressure of the eye  22  against a lower lip  27  of the locking bolt  28  rotates the locking bolt  28  to bring the tooth  30  through the eye  22 . After the lid  12  is closed, the eye  22  may not be freed to open the lid  12  without counter rotation of the locking bolt  28  caused by upward pressure on the tooth  30  by the eye  22 . 
     The locking bolt  28  is joined by means of a shaft  32  to a ward plate  34  which rotates in tandem with the locking bolt  28 . In a preferred embodiment, the ward plate  34  is a 90 degree sector of a circular disk. As such, the shaft  32  is attached to the center of the disk, perpendicular to the face of the disk. In the open position shown in FIG. 3, the ward plate  34  has its left and right radial faces oriented at approximately plus and minus 45 degrees from vertical. In the closed position of FIG. 4, the right face of the ward plate  34  is vertical and the left face of the ward plate  34  is substantially horizontal. 
     A return spring  56  connects to the ward plate  34  at a point near the top of its left wall at a point fixed with respect to the ward plate  34  and so that the line between these points passes above the axis of rotation  31  to provide a clockwise return torque to the ward plate  34 . Thus, ward plate  34  and locking bolt  28  will move to a fully open position absent the influence of the eye  22 . 
     Positioned beneath the left face of the ward plate  34  is a contact set providing a “lid closed” switch  36  which in the open position of FIG. 3 is closed but which is opened by pressure of the left face of the ward plate  34  on the support of the bottom contact of the “lid closed” switch  36 , when the lid  12  is closed. Thus, “lid closed” switch  36  provides an indication that the lid  12  is closed. 
     Positioned over the top of the ward plate  34  is one end of an armature  38  of an electrically actuated stop  40 . The armature  38  is hinged at its other end removed from the ward plate  34 , to a coil frame  42  which supports an electromagnet coil  44  positioned about a vertical core  46  positioned beneath the armature  38 . Core  46  is a permanent magnet insufficiently strong to attract armature  38  downward alone, but sufficient to hold armature  38  downward once contact between armature  38  and core  46  has been obtained. Alternatively, the core  46  may be a high remnant magnetizable material that will retain sufficient magnetization to hold the armature in a closed position. 
     A first polarity of electrical current passing through leads  48  of the coil  44  will produce a magnetic field such as will augment the magnetic field retained by the core  46  (or reverse the magnetization of the core  46  in the case of the high remnant magnetizable material), and will thereby attract armature  38  downward toward the top of core  46 . Once so attracted, the armature  38  will remain in the downward position held by the magnetism of the core  46 . A second polarity of electrical current, opposite to that of the first polarity of electrical current drawing the armature  38  downward, will release the armature  38  to move upward as biased by a spring  54 . 
     Referring now to FIG. 8 in an alternative embodiment, a donut of permanent magnet material  47  may be placed about the core  46  to provide the necessary magnetic attraction instead of or in addition to the core  46 . 
     When the lid  12  is in the open position as shown in FIG. 3, armature  38  may not be drawn downward into contact with core  46  because the free end of the armature  38  strikes the upper circumference of the ward plate  34 . In the closed position of FIG. 4, however, the ward plate  34  has rotated such that armature  38  may move downward into contact with core  46  and, in doing so, the end of armature  38  is in a position to abut the right most wall of ward plate  34  preventing counter rotation to the open position of FIG.  3 . As a result of the inner connection between the ward plate  34  and the locking bolt  28 , the locking bolt  28  may not rotate when armature  38  is drawn downward against core  46  and locking bolt  28  therefore holds lid  12  closed in a locked position as a result of its inner action with the eye  22 . Thus, this first polarity of electrical current may be termed a lock signal and the latch assembly  24  may be considered to be in a locked state when the armature  3   8  is attracted to the core  46 . 
     Referring to FIG. 4, once armature  38  has been drawn down to core  46 , power may be disconnected from leads  48  and yet armature  38  will remain downward held by the residual magnetism of core  46  or the donut  47 . 
     The latch assembly  24  may be released by moving the armature  38  upward again by means of applying to leads  48  the second polarity of current previously described which causes the coil  44  to produce a magnetic field opposing that of the core  46  or donut  47  releasing the armature  38 . This second polarity of electrical current is termed the unlock signal. The latch assembly  24  may be considered to be in an unlocked state when the armature  38  is released from the core  46 . 
     Again, when power is disconnected from leads  48 , the armature  38  will remain in an upward position held by the biasing spring  54 . Thus, it will be noted that the latch assembly  24  is bistable requiring no power to remain in either the unlocked or locked state and remaining in the last unlocked or locked state indefinitely when power is removed. 
     A contact set forming a “lock enabled” switch  50  has one contact supported at the lower surface of armature  38  by a cantilevered contact support spring  52  (visible in FIG. 2) and the other contact positioned beneath the armature  38  so that the contact set is open when the armature  38  is in an unlocked state shown in FIG.  3  and closed when the armature  38  is in a locked state shown in FIG.  4 . “Lock enabled” switch  50  provides a signal indicating that a locking has occurred as opposed to simply a closure of the lid  12  and allows the motor of drive motor assembly  16  to run. 
     Referring now to FIGS. 5 and 6, the mechanical elements of the latch assembly  24  described in FIGS. 2 through 4 are controlled by logic circuitry  57  receiving AC power from a power line  58  (that generally provides switched power to the washer  10 ) and completing a circuit through a ground  60 . The washing machine timer  13  (shown generally in FIG. 1) provides a spin cycle signal  62  in the form of AC voltage when the spin basket  14  is to be spun by drive motor assembly  16 . 
     During operation of the washing machine  10 , the spin cycle signal  62  is received by a terminal  64  on the housing  55  of the latch assembly  24 . The terminal connects the spin cycle signal  62  through the “lock enabled” switch  50  to a second terminal connected to the motor of the drive motor assembly  16 . In the unlocked state, “lock enabled” switch  50  is open and therefore no current passes to the motor of the drive motor assembly  16 . 
     The spin cycle signal  62  also connects through diode  66  and limiting resistor  68  to a “lock signal” capacitor  70  which, when the spin cycle signal  62  is present, begins charging. The charging is indicated by arrow  73 . During this charging, “lock signal” capacitor  70  stores energy that will be shunted through the coil  44  of the latch assembly  24  to lock that mechanism as has been described and also provides a timing signal by means of its decreasing voltage as it discharges. Specifically, when the charge on capacitor  70  climbs to a first predetermined level of approximately 24 volts, it actuates switching circuit  72 . Switching circuit  72  is connected to shunt an “unlock signal” capacitor  74  discharging that capacitor  74  when switching circuit  72  is actuated. 
     The “unlock signal” capacitor  74  is connected between ground, on one side, and a junction between “lid closed” switch  36  and coil  44  on the other side. The “lid closed” switch  36  and coil  44  are connected in parallel and their other end is connected through switching element  76  to the side of the “lock signal” capacitor  70  receiving current from limiting resistor  68 . 
     When “lock signal” capacitor  70  reaches a second voltage (approximately 36 volts) greater than the voltage triggering switching circuit  72 , switching element  76  conducts allowing current to flow from “lock signal” capacitor  70  through coil  44  (if the lid is closed and “lid closed” switch  36  is open) into “unlock signal” capacitor  74  which was previously discharged as indicated by arrow  77 . When the lid  12  is closed, this current from the “lock signal” capacitor provides the lock signal causing armature  38  (shown in FIG. 4) to be drawn downward locking the lid  12  in the locked position. The latching of armature  38  closes “lock enabled” switch  50  which allows current to flow to motor of the drive motor assembly  16 . 
     Note that if the lid  12  is open at the time the spin signal is received, such as would indicate a child may be entrapped, then “lid closed” switch  36  is closed and the current passes solely through short circuit created by “lid closed” switch  36 . In this case, the armature  38  is not drawn downward into the locking position. 
     As the voltage on “lock signal” capacitor  70  drops with its discharge, switching circuit  72  opens allowing a charge to accumulate on the “unlock signal” capacitor  74  from the flow of current along path  77 . “Unlock signal” capacitor  74  provides a reserve of power that will be used to unlock the latch assembly  24  at the end of a coast down after the spin cycle or in the event of a power failure both as will be described. The transfer of power from “lock signal” capacitor  70  to “unlock signal” capacitor  74  ensures that any time sufficient power is available to lock the latch assembly  24  that reserved power exists to unlock the latch assembly  24  and the form of charge on “unlock signal” capacitor  74 . While power is available to the washing machine  10 , as is normally the case, the charge on “unlock signal” capacitor  74  is maintained by a path from the power line  58  through diode  78  and limiting resistor  81 , through coil  44  or “lid closed” switch  36 . 
     At the conclusion of the spin cycle, the spin cycle signal  62  is disconnected and switching element  76  resets to an open state. When the spin basket  14  has coasted to a stop, switching element  80 , which is connected between the side of the parallel connection of “lid closed” switch  36  and coil  44  that receives power from the spin cycle signal  62  and ground, serves to provide a discharge path for the energy in the “unlock signal” capacitor  74  backwards through coil  44  to ground in order to produce the unlock signal to unlock the latch assembly  24 . Thus energy from the lock signal may be recycled as an unlock signal later if power is lost. 
     Switching element  80  provides a discharge path for “unlock signal” capacitor  74  if a periodic signal of a predetermined rate (rotation signal  21 ) is no longer received from sensor  20 . Sensor  20  provides a path from switching element  80  to ground each time the magnet on the spin basket  14  passes the sensor  20  as the spin basket  14  spins. 
     The “unlock signal” capacitor  74  effectively powers the switching element  80  and its associated logic circuitry in the event of a power failure. 
     When switching element  80  moves to a conducting state, it oscillates between a conducting and non-conducting condition such as allows capacitor  74  to slowly recharge (if power is available) and then rapidly discharge through switching element  80  providing repetitive unlock signals through coil  44 . Such repetitive signals ensure that coil  44  unlocks in the unlikely event that one or more unlocking signals are jammed, for example, by the user pulling upward on the lid  12  such as may cause the armature  38  to be trapped against the ward plate  34  as shown in FIG.  4 . 
     Note that if the wire from sensor  20  is broken, then shortly after the spin cycle is initiated, the “unlock signal” capacitor will charge up by virtue of the locking signal and an unlock signal may be produced by switching element  80 . This unlock signal will open “lock enabled” switch  50  stopping the spinning of the motor despite the presence of the spin cycle signal  62 . This stopping of the motor of the drive motor assembly  16  provides an indication to the user that a repair is required and avoids needless exposure of the user to the rotating spin basket  14  when the circuit cannot maintain a lock state for lack of information about whether the spin basket  14  is in motion. 
     Referring now to FIG. 7, the circuit of FIGS. 5 and 6 initially detects the initiation of a new spin cycle signal at decision block  100 . A new spin cycle in this case indicates a transition from no spin cycle to a spin cycle signal. 
     If there is no new spin cycle signal during a washing cycle, the circuit proceeds to decision block  102  to determine whether the spin basket  14  is rotating as detected by sensor  20 . If not, as would also be the case, for example, in a wash cycle, the circuit proceeds to process block  104  and an unlock signal in the form of a pulse is transmitted to the coil  44  of the electrically actuated stop  40  and the circuit returns back to the decision block  100 . Thus, in situations where a lid lock is not required, that is, there is no spin cycle and the spin basket  14  is not rotating as might be the case in a recently concluded spin cycle, the electrically actuated stop  40  receives repeated unlocked pulses to ensure that the latch assembly  24  is unlocked. 
     Upon an initiation of a spin cycle signal at decision block  100 , the circuit moves to decision block  106  where it is determined whether the lid  12  is closed (by means of “lid closed” switch  36 ). If the lid  12  is closed, the circuit proceeds to process block  108  and the lid  12  is locked by actuation of coil  44  of electrically actuated stop  40  which in turn closes “lock enabled” switch  50  allowing the motor to start. The circuit then proceeds to decision block  102  as has been described to test for rotation of the motor. 
     Normally at decision block  102 , there will be rotation detected because the motor of the drive motor assembly  16  was started at process block  108  and the sensor  20  is properly connected and therefore the circuit loops back to the top of decision block  102  and continues to cycle through decision block  102  for as long as the spin basket  14  is rotating. 
     When the spin cycle ends, the motor of the drive motor assembly  16  no longer receives power and the spin basket  14  begins to coast. When rotation is no longer detected by sensor  20 , the circuit breaks out of the loop of decision block  102  and proceeds to process block  104  where the latch assembly  24  is unlocked. The circuit then begins the cycling between decision block  100 , decision block  102 , and process block  104  as has been previously described, providing repeated unlock signals. 
     During spinning of the spin basket  14  when the circuit is checking rotation of the spin basket  14  at decision block  102 , power may be removed from the washing machine  10  in a power failure or an attempt to defeat the lid lock. Normally the spin basket  14  will coast down prior to enough energy being lost from capacitor  74  that a lid unlocking is no longer possible. 
     The basic circuitry used to provide a fast release lid lock when rotation of the spin basket  14  ceases may also help prevent entrapment of a small child if the lid is closed while the spin cycle is activated. Referring still to FIG. 7, in this circumstance, at process block  100 , a spin cycle signal is detected and the circuit proceeds to decision block  106 . At decision block  106 , the lid  12  is not closed and therefore the circuit proceeds to decision block  112  which again checks for the presence of a spin cycle signal  62 . If that spin cycle signal  62  is still present, the circuit loops back to this decision block  112  indefinitely, thus avoiding a locking and starting of the motor of the drive motor assembly  16 . Only when the spin cycle signal  62  is turned off and on again by the user with the lid closed, does the circuit proceed to decision block  102  to check for a rotation signal  21  per a normal end of a spin cycle, ultimately ending up again at decision block  100 . 
     Thus, in order for the motor of the drive motor assembly  16  to be started for the spin cycle, the lid  12  must be closed prior to the initiation of the spin cycle signal  62  avoiding the entrapment situation. 
     In an alternative embodiment shown in FIG. 9, the spin sensing switching element  80  and sensor  20  are eliminated and a timer  150  used instead. The timer  150  provides an unlock signal  158  to a switching circuit  149 , the latter which shunts one end of coil  44  to ground, the other end being connected to capacitor  74  so that the discharge of capacitor  74  through coil  44  causes an unlatching of the latch assembly  24 . 
     Referring also to FIG. 11, the operation of this alternative embodiment is essentially the same as that described above with respect to FIGS. 5-7 except at process block  102  (now labeled  102 ′) rotation is not sensed, but a fixed period of time after the cessation of the spin cycle signal is sensed. This fixed period of time is set to approximate the maximum time of coasting rotation of the spin basket under variations in load, weight, speed and friction and inertia for the spin basket, once power to the motor  16  has stopped. When this period of time has elapsed, the lid may be opened in much the same way as when the sensor  20  of the previous embodiment indicated that spinning of the spin basket  14  had stopped. 
     Referring now to FIG. 10, the timer  150  may be a digital counter  151  such as a  4020  integrated circuit well known in the art, receiving at its clock input (CLK) from the AC voltage of the power line  58  attenuated by attenuating resistor  152 . In this manner, the counter counts cycles of the 60 Hz voltage of power line  58 . Outputs Q 13  and Q 14  of the counter representing count values of 2 11  and 2 12  are combined by means of diode  154  and resistor  156  acting as a simplified AND gate to provide a unlock signal  158  to the switching circuit  149 . 
     The counter  151  is held reset by line  166  communicating with the spin cycle signal  62  so as to hold the counter at a count value of zero until the spin cycle has ceased. Then the counter begins counting and when the Q 13  and Q 14  outputs go high (representing a count of 6,144 line cycles or 102.4 seconds), the unlock signal is generated activating the shunting circuitry  149  pulling down the lead  48  of coil  44  attached to capacitor  74  to ground causing an unlock signal to pass through coil  44 . Capacitor  75  causes a two second delay in the unlocking action. 
     In the event of a power failure, the voltage on capacitor  74  is monitored by zener diode  162  which ceases conducting as the voltage on zener diode  162  drops below a predetermined threshold. This ceasing of conductance turns off transistor  164  asserting the unlock signal  158  and causing unlocking of the latch despite the loss of power to the counter  151 . The time constant for the decay of the voltage on capacitor  74  to the predetermined threshold is set to be nominally 250 seconds so, even with long term capacitor degradation of up to 50% and a tolerance factor of 10%, the time constant is substantially longer than that which would be provided by the operation of counter  151 . Thus in the event of power failure, access to the clothes is allowed, albeit at a time somewhat after access would be allowed were the counter  151  working, ensuring that the spin basket  14  has stopped spinning. 
     If power line  58  has been disconnected, the occurrence of the unlock signal causes capacitor  74  to fully discharge and only a single unlock pulse is produced. If however power is still present through the power line  58 , capacitor  74  recharges as described above and switching circuit  151  is reset to be reactivated upon the recharging of capacitor  74  to produce a series of unlock signals ensuring complete unlocking. 
     A neon bulb  170  or other indicator light is placed in series about contacts  172  of the cycle timer  13  whose closure creates the spin cycle signal  62  so as to illuminate when the spin cycle is complete providing a visual indication to the user that the spin mode has ended and that the spin basket  14  is coasting to a stop with the lid locked. 
     The above description has been that of a preferred embodiment of the invention. It will occur to those that practice the art that many modifications may be made without departing from the spirit and scope of the invention. In order to apprise the public of the various embodiments that may fall within the scope of the invention, the following claims are made.