|Publication number||US3324690 A|
|Publication date||Jun 13, 1967|
|Filing date||May 6, 1965|
|Priority date||May 6, 1965|
|Publication number||US 3324690 A, US 3324690A, US-A-3324690, US3324690 A, US3324690A|
|Inventors||Button Charles T|
|Original Assignee||Texas Instruments Inc|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (2), Referenced by (15), Classifications (8)|
|External Links: USPTO, USPTO Assignment, Espacenet|
cfT. BUTTON WASHING MACHINE June 13, 1967 3 heets-Sheet 1 Filed May 6, 1965 June 13, 1967 c. T. BUTTON WASHING MACHINE 3 he'ets-Sheet 2 Filed May 6, 1965 June 13, 1967 c. T. BUTTON 3,32
WASHING MACHI NE Filed May 6, 1965 3 heets-Sheet 5 United States Patent 3,324,690 WASHING MACHINE Charles T. Button, Dayton, Ohio, assignor to Texas I struments Incorporated, Dallas, Tex., a corporation of Delaware Filed May 6, 1965, Ser. No. 453,591 3 Claims. ((3. 68-23) This invention relates to washing machines and more particularly to a washing machine actuator employing a mechanically resonant agitator drive.
The development of controllable electromagnetic drive systems which can be freely reversed or programmed in behavior and the design of such electromagnetic structures which can be directly coupled to a washing machine agitator have made possible the construction of a washing machine which includes exceptionally few components and which is, for this reason, relatively simple in construction and reliable in operation. However, the relatively high peak torque required for agitator oscillation has required that relatively massive actuator components be employed to provide this torque.
Among the several objects of this invention may be noted the provision of a washing machine construction in which the peak torque required from the drive means is substantially reduced for a given agitator movement; the provision of such a construction in which energy is stored during nonpeak torque conditions and is expended in providing the desired peak torque; the provision of such a construction in which the actuator is operated as a resonant system; the provision of such a construction including an exceptionally simple method of coupling the washing machine basket to the actuator for a spin dry operation; the provision of such a construction which is extremely reliable; and the provision of such a construction which is relatively simple and inexpensive to manufacture. Other objects and features will be in part apparent and in part pointed out hereinafter.
A washing machine construction according to the invention will typically include a tub, an agitator journalled for rotation Within the tub and a reversible drive means for oscillating the agitator. In one aspect of the invention, the peak torque required from the drive means during agitation is reduced by operating the agitator as part of a resonant system with spring means being provided for storing energy and for applying a restoring torque at the oscillatory peaks of agitator movement. In another aspect of the invention, the apparatus also comprises a rotatable basket for holding clothes to be washed and the spring means interconnects the agitator and the basket so that unidirectional rotation of the agitator is coupled to the basket for the extraction of moisture by spinning.
The invention accordingly comprises the constructions hereinafter described, the scope of the invention being indicated in the following claims.
In the accompanying drawings in which various possible embodiments of the invention are illustrated,
FIG. 1 is an exploded view of the major components of a washing machine of the present invention;
FIG. 2 is an exploded view of the actuator of the washing machine of FIG. 1;
FIG. 3 is an assembled view of the actuator; and
3,324,69b Patented June 13, 1%67 FIG. 4 is a bottom view of another embodiment of the torsion spring means of the actuator.
Referrin now to FIG. 1, the washing machine therein illustrated comprises a conventional sheet metal cabinet or housing 11. A base plate 13 is supported within housing 11 and it is upon this base plate that the major clothes washing components are mounted. The base plate 13 is ribbed for strength as at 15 and includes a tubular central post 17 projecting upwardly therefrom. An actuator 19 is secured to the underneath side of base plate 11 by screws 21. Actuator 19 is described in greater detail hereinafter but, for the present, it may be noted that the actuator includes a pair of upwardly extending coaxial shafts 23 and 25 which project upwardly through spindle 17. The outer tubular shaft 23 is shaped at its upper end to engage and rotate with a conventional washing machine basket assembly while the upper end of the central shaft 25 includes a key slotted portion 26 for receiving a conventional Washing machine agitator.
A tub 27 is secured to the upper side of base plate 13. As will be apparent to those skilled in the art, tub 27 and base plate 13 will include appropriate openings for the necessary water inlets and drains and suitable fixtures for the mounting of pumps and valves. These provisions, however, are conventional and, since they do not pertain to the present invention, are not shown or described further herein.
A perforate clothes receiving basket 31 fits within tub 27 and includes a central sleeve 33 which fits rotatably over spindle 17. The upper end of sleeve 33 includes surfaces which mate with the upper end of the tubular actuator shaft 23 so that basket 31 is secured to and is driven by shaft 23.
An agitator 35 is provided which includes a plurality of radial blades 37 and a hollow central post portion 39 which fits loosely and rotatably over sleeve 33 of basket 31. The upper end of post portion 3a includes an internaL ly slotted part 41 by means of which the agitator can be keyed to the mating portion 26 of the central actuator shaft 25. Thus the agitator 35 is secured to and driven by shaft 25. A cap 42 covers part 41.
The construction of actuator 19 itself can be seen in FIGS. 2 and 3. Mechanical energy for operating the washing machine is obtained from an electromagnetic device 45 of generally pancake configuration. Device 45 includes a stator 47 which is wound with a multiplicity of energizing windings 49, These windings can be sequentially energized by polyphase alternating or pulsating current to provide a plurality of rotating magnetic poles. A squirrel cage rotor 51 is mounted directly on agitator shaft 25 for rotation within stator 47. While direct connection of rotor 51 through shaft 25 to agitator 35 is preferred, this connection can also be made through appropriate reduction gearing or belting which provides a positive mechanical coupling between these elements. A bottom plate 53 covers the underside of electromagnetic device 45 and retains a thrust bearing assembly 55 for supporting shaft 25.
The rotor 51 of electromagnetic device 45 can be driven in either direction. A preferred form of electronic control for providing sequential energization of windings 49 in either rotational direction is that shown in my copending application, Ser. No. 425,265, filed Jan. 13, 1965 and entitled, Electromagnetic Apparatus. A reversible DC. motor or other driving source can also be used although it is preferable that an A.C. construction be employed.
Mounted on shaft just above rotor 51 is a crank member 57. Crank member 57 is secured against rotation relative to shaft 25 by a screw pin 59 which is threaded into member 57 and extends into a transverse bore 61 in shaft 25.
The tubular, basket-supporting shaft 23, discussed previously in describing the overall construction of the washing machine, includes at its lower end a transverse flange 65. Assembled on shaft 23 just above flange 65 is a torsion spring assembly 67 which includes a pair of oppositely wound spiral springs 69 and 71. Springs 69 and 71 are kept in their proper planes by separator discs 73-75. The inner end of each of springs 69 and 71 terminates in a radial key portion, 77 and 79 respectively. Key portions 77 and 79 are adapted to fit into the opposite sides of a slot 81 which is cut into a flanged, spring carrying hub 83. Hub 83 is secured against rotation relative to tubular shaft 23 by a screw pin 85 which threads into hub 83 and extends into an aperture 87 in the side of tubular shaft 23. Thus the inner ends of springs 69 and 71 will rotate with shaft 23. The outer end of each spiral spring 69 and 71 terminates in a hook portion, 89 and 91 respectively.
A flanged thrust bearing 93 fits within tubular shaft 23 underneath flange 65 and the entire tubular shaft assembly, including the torsion spring components, fits over shaft 25 as may be seen in FIG. 3. The coaxial shafts are assembled so that the crank member 57, which rotates with shaft 25, is engageable with the hook portions 89 and 91 of springs 69 and 71. Thus, shaft 25 is resiliently coupled, through springs 69 and 71, to shaft 23 or, stated in terms of the overall washing machine construction, agitator is resiliently coupled to basket 31. The position of basket 31 thus establishes the nominal rest position of agitator 35.
It will be apparent to those skilled in the art that the mass of agitator 35 and attached rotor 51 and the resilience of springs 69 and 71 constitute a mechanically resonant or oscillatory system in which the springs exert a restoring force which tends always to return the agitator to its nominal rest position. Since the rotational inertia of basket 31 is typically greater than that of the agitator rotor assembly, the resonant frequency of the agitator system will not be substantially affected by the fact that the inner ends of springs 69 and 71 are anchored relative to basket 31 rather than being attached to some fixed component of the machine. The basket will oscillate somewhat during oscillation of the agitator but the basket oscillations will, at resonance, typically be small and out-ofphase with the agitator movements. Any excursions of basket 31 will be further restrained by the presence of water and clothes within the basket. Optionally, mass may be added to the basket to modify its behavior. However, if desired, these basket oscillations can be eliminated by the addition of a brake or pawl arrangement which locks the basket relative to the housing.
The operation of actuator 19 in the washing machine construction illustrated is as follows. For agitation, the windings 49 are energized'in a pattern such that the sequence of energization periodically reverses direction of rotation relative to stator 47. Thus rotor 51 is driven first in one direction and then in the other. Agitator 35, being directly coupled to rotor 51 through shaft 25, will experience the same oscillatory angular excursions. The total torque required to produce this oscillatory motion reaches a peak, due to the inertia of the system, just as agitator 35 reverses its direction of rotation. Since springs 69 and 71 exert a maximum restoring torque at the peaks of the oscillatory excursions, the amount of torque which must be generated electromagnetically is substantially reduced. Thus, the electromagnetic device need be only of sufficient size to provide the energy absorbed in the clothes washing operation and does not need to be of such size as would be required to provide the whole peak torque needed for reversing the direction of rotation of the agitator in a given oscillatory motion. Stated in another way, the excursions caused by a given power input to windings 49 are much greater when the agitator is incorporated into a mechanically resonant system than those which would be produced when it is operated free of any resilient restoring force.
While it is desirable that the agitation be performed at a frequency which is at or near a resonant peak, the restoring force exerted by the springs will provide a considerable reduction in the peak electromagnetic torque required over an appreciable range of frequencies or component values. As long as the spring constant is not more than twice that required for resonance at the desired or predetermined operating frequency, an advantage by way of torque reduction is obtained. Stated in another way, a torque advantage is obtained if the resonant frequency is not more than double the operating frequency. To adjust for the desired effect, the rotational inertia of the various components and the spring constant can be varied. Typically, it is desirable to choose these parameters to produce agitator resonance at the highest frequency of operation contemplated, the torque reduction being greatest at resonance. At lower frequencies the peak torque required is lower anyway, since the inertia forces are less, so that the electromagnetic system can supply the necessary torque even though the benefit obtained through the use of the torsion spring is not as great as at resonance.
To provide a spin dry operation for the centrifugal extraction of moisture, windings 49 are sequentially energized in one rotational direction only. Springs 69 and 71 are deflected only to the extent necessary to overcome the drag of basket 31. The basket then spins with the agitator 35 and rotor 51. It will thus be noted that both the agitation and the spin dry operations are accomplished without the use of clutches or other motion transfer devices. Rather, the same mechanical connections always exist between agitator 35 and basket 31 with the resiliency of springs 69 and 71 providing the decoupling for oscillatory motions which is needed for agitation.
While spiral springs 69' and 71 have been shown by way of illustration, it should be understood that other types of decoupling or energy storing spring means could also be used. One such alternate construction is shown in FIG. 4 wherein tension springs are employed. The apparatus is shown from the bottom, looking up at the clothes holding basket 31. A crank member 101 having a pair of arms 103 and 105 is secured to agitator shaft 25 by a pin 107. Each of arms 103 and 105 includes an attachment pin 109. A helical tension spring 111 extends from each such pin to a post 113 set into basket 31 near its periphery. It will be apparent to those skilled in the art that, in this modification also, the agitator assembly and the springs 111 constitute 'a resonant or oscillatory system and that, when the agitator is displaced in oscillation, energy will be alternately stored and released by springs 111 so as to reduce the peak torque required from the actuator which drives the agitator.
In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.
As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
What is claimed is:
1. A washing machine comprising:
a basket journalled for rotation within said tub;
an agitator journalled for rotation within 'said basket;
reversible electromagnetic drive means including a rotor which is directly and positively coupled to said agitator; and torsion spring means interconnecting said basket and said agitator, whereby unidirectional operation of said drive means produces rotation of said basket for moisture extraction by spinning and periodically reversing operation of said drive means produces oscillation of said agitator with said basket being decoupled from the oscillatory movement of said agitator by said spring means. 2. A washing machine according to claim 1 in which said torsion spring means comprises a pair of oppositely wound spiral springs.
References Cited UNITED STATES PATENTS 2,588,963 3/1952 Ch-apin 68-23 2,660,044 11/1953 Williams 6823 WILLIAM I. PRICE, Primary Examiner.
WALTER SCHEEL, Examiner.
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|EP0239261A2 *||Mar 4, 1987||Sep 30, 1987||FISHER & PAYKEL LIMITED||Improvements in or relating to drives for clothes washing machines|
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|U.S. Classification||68/23.7, 68/133|
|International Classification||D06F37/40, D06F37/30|
|Cooperative Classification||D06F37/40, D06F37/304|
|European Classification||D06F37/40, D06F37/30C|