US 3285419 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
Nov. 15, 1966 T. R. SMITH EXTRACTOR APPARATUS DRIVE CONTROL 5 Sheets-Sheet l Filed June 4, 1963 Nov. 15, 1966 T. R. SMITH 3,285,419
EXTRACTOR APARATUS DRIVE CONTROL Filed June 4., 1963 5 Sheets-Sheet 2 Nov. 15, 1966 T. R. SMITH 3,285,419
EXTRACTOR APPARATUS DRIVE CONTROL Filed June 4, lees s sheets-sheet s VEA/Tof? Ufo/WAS A?. SM/TH Patented Nov. 15, 1966 3,285,419 EXTRACTOR APPARATUS DRIVE CONTRL Thomas R. Smith, Newton, Iowa, assignor to The Maytag Company, Newton, Iowa, a corporation of Delaware Filed .lune 4, 1963, Ser. No. 285,411 9 Claims. (Cl. 210144) This invention relates to centrifugal extractors and has particular reference to washing machines which are operable through a washing cycle including at least one extraction operation. More specifically, this invention concerns a speed control system for driving a centrifugal extractor at the maximum speed commensurate with vibration caused by unbalanced loading for insuring an optimum fluid extraction.
In certain types of clothes washing machines, the washing liquid is centrifugally extracted from the clothes by spinning a basket. In washing machines employing centrifugal extractors, the washer and extractor assembly may be mounted for gyrating or oscillatory motion about a suitable support as in vertical axis washers or for arcuate motion as in horizontal axis machines. Since the wet clothes are seldom distributed exactly evenly about the spin axis, ythe machine is subject to vibrations as a result of forces developed during the centrifuging operation. This problem is well recognized in the field and many attempts have been made to suppress, or eliminate, the vibrations.
Various systems have been employed for mounting and centering the assembly and dampening, or reducing, the vibrations thereof. In some systems, efforts to solve the problem presented by rotation of out-of-balance loads include devices responsive to vibrations of a predetermined magnitude for opening the circuit to the electric motor so that the machine will stop upon encountering excessive out-of-balance loading. Other eiorts to solve the problem of out-of-balance loading provide that a brake be applied so as to arrest the rotation and out-ofbalance caused movement of the spinning extractor. Still other systems employ clutch devices for interrupting rotation of the machine to reduce the speed of the extractor, or to stop it entirely.
Stopping the extractor is undesirable, since the unbalance is due, in part, to the water contained in the unevenly distributed clothes. If the water is 4continued to be eliminated from a load which is causing extreme vibrations, it is possible that upon continued rotation enough water will be extracted to reduce the unbalanced condition, and to allow higher rotational speeds without excessive vibrations.
The present invention thus provides a speed control system whereby the spinning and ythe water extraction continues at a maximum speed permissible with existing unbalanced conditions. Spin speed is made responsive to the amount of unbalance caused movement of the washing container by a system which makes the drive system directly responsive to vibrations caused by spinning unbalanced loads.
It is therefore an object of this invention to provide an improved system for controlling operation of .a lluid extractor to eliminate problems of excessive vibration caused by unbalanced spinning loads while assuring continued fluid extraction.
It is also an object of this invention to provide an improved system for controlling the rotational speed of a fluid extractor to eliminate vibration problems caused by unbalanced `loads contained therein while allowing continued operation thereof.
It is a further object of this invention to provide an improved speed control system for a washing machine which is responsive to vibrations caused by unbalanced loads during the extraction operation.
It is still a further object of this invention to provide a speed control system for a washing machine in which drive belt tension is responsive to vibrations caused by unbalanced spinning loads for controlling the spin speed to allow a maximum spin speed commensurate with the amount of unbalance.
Further objects and advantages of this invention will become evident as the invention is more fully described hereinafter in the specification, and drawings and claims appended thereto.
ln the drawings which illustrate two embodiments of the device and wherein like reference numerals are used to designate like parts:
FIGURE l is a side elevational view of a vertical axis automatic washing machine embodying the present invention;
' FIGURE 2 is an enlarged view of the drive motor and mounting thereof showing the present invention as adapted to the automatic washer of FIGURE l;
And FIGURE 3 is a rear elevational view of a washerdrier combination embodying the present invention.
Referring now to the accompanying drawings, there is illustrated a vertical axis automatic washing machine in FIGURE 1 having a base frame 10 supported by the Aadjustable leg members 11 and mounting cabinet enclosure 12 which is provided with a hinged Iaccess door 13. The access door 13 normally covers a recessed rectangular countersunk throat 14 which terminates in a circular loading opening 15.
Mounted on a friction damper surface of a truncated mounting dome 16 positioned in the central region of base frame 10 is the support member 17. Rigidly connected to and extending upwardly and outwardly from the support member 17 to form an inverted tripod are three tub braces =18. Support member 17 and tub braces 18 are resiliently connected to base frame 10 by means of three equally spaced centering springs 19 extending between each of the three tub brace members 18 'and base frame 10. The springs l19 resist rotation of support member 17 about its vertical axis relative to base frame 10, although they permit its nutational movement relative to said base frame.
Extending through lan opening in dome 16 and threaded into the lower end of support member 17 is drive assembly 21. This drive assembly and its mounting is more particularly described in U.S. Patent No. 2,948,372 to J. D. Goodlaxson issued August 9, 1960.
Connected at the upper extremity of tub braces 18 is a non-rotatable and generally imperforate container or ltub 23 which is provided at its upper end with a tub loading opening 24 aligned with the opening 15 formed in cabinet 12.
Rotatably mounted within tub 23 is the perforate receptacle or clothes basket 25 which is rigidly connected to a stub shaft (not shown) journalled in a bearing (not shown) carried in the bottom of tub 23. The stub shaft is directly connected to the gear case assembly 26 affixed to the upper end of spin tube 28. The spin tube 28 is supported by and journalled in a thrust bearing (not shown) retained in support member 17 and is capable of being yrotated at spin speeds through drive assembly 21 and by input pulley 29 through drive belt 30 and the double motor pulley 31 attached to the shaft of the reversible drive motor 33.
When motor 33 is reversed by the switching of timer mechanism 34, electrically connected to said motor, the reversed rotation of input pulley 29 produces an oscillatory movement of agitator 35 positioned within basket 25. Agitator 35 is powered through a central shaft 36 journalled within spin tube 28. This central shaft 36 is driven by input pulley 29 and is connected to a conventional type motion converting mechanism (not shown) mounted within gear case 26 and is therein connected to an output shaft (not shown) splined to agitator 35. In the automatic washing machine thus illustrated, the clockwise rotation of the drive shaft of motor 33, as viewed from the top of the motor, produces an oscillatory movement of agitator 35 of approximately 52 cycles per minute during the washing operation while rotation of said drive shaft in a counterclockwise direction during fluid extraction or spin-out operations produces rotation of the basket 25 at a speed of approximately 618 revolutions per minute.
In the embodiment shown in FIGURES 1 and 2, it is noted that while spin tube 2S is effectively supported by support member 17, it and the concentric inner drive shaft 36 actually pivot on a point ydetermined by the intersection of the radii of curvature of the mating surfaces of mounting dome 16 and support member 17. This point is also the intersection of the shafts axis of rotation with the substantially horizontal plane intersecting the pulley 29 at the centerline of belt groove 38, thus minimizing direct variations in belt tension during the gyratory movement of the shafts.
It is thus seen that certain elements of the washing mechanism including drive mechanism 21, support member 17, tub braces 18, and outer tub 23 are assembled to form a unitary assembly, generally indicated as 40, which is capable of nutational or oscillatory movement upon mounting dome 16. It is also thus seen that when clothes basket 25 is rapidly rotated while containing an unbalanced load, the forces due to the unbalanced load ywill be transmited to the aforementioned unitary assembly to cause said nutational or oscillatory movement.
The outer tub 23 is provided with a bottom wall in which is formed a gutter having its lowermost portion converging into a drain outlet conneced to pump 41 by the flexible drain hose 43. Water pump 41 which is driven by belt 44`is a bi-directional pump which pumps fluid through hose 43 toward the tub during agitation periods and pumps fluid away from that tub to an external drain during the fluid extraction periods.
As best seen in FIGURE 2, drive motor 33 is movably supported on base frame so as to allow a variable degree of tension in drive belt 30 as during periods of rotational acceleration. Drive motor 33 is attached to movable motor mount 45 which is in turn supported by wheel members 46. A-ttached to base 10 is the fixed motor mount 48 having side walls 50 which serve as guides or ways for wheel members 46. Springs 49 serve to bias motor 33 and motor pulley 31 away from drive pulley 29 so as to maintain proper belt tension.
Since basket 25 is ordinarily loaded at random with vvarious Itypes and weights of garments, it is not unusual to encounter a condition of unbalanced loading within that clothes receptacle. Upon rotation of the basket 25 under these conditions of acentric loading, certain unbalanced centrifugal forces are produced within basket 25 and transmitted to unitary assembly 40. This causes the unitary assembly 40 to deviate from its normal vertical position and causes basket 25 to rotate about an axis which nutates or oscillates about the normal vertical axis.
While the resilient mounting of support 17 serves to dampen these nutational movements about the vertical axis ond partially isolates the disturbing unbalanced forces from base frame 10, the movements of the entire tub assembly 40 from the vertical axis may, under cera-tin excessivelyunbalanced load condition, be of such magnitude as to produce violent vibration problems. For this reason, it is necessary that a speed control system be ern- Vloyed which will allow continued operation of the exy,factor to insure the best possible fluid extraction from the loadbut which will limit speed to a level above which exsive vibrations are created.
The present invention provides a control system for preventing excessive vibrations due to unbalanced spinning loads while allowing continued operation of the machine through the extraction operation by limiting the speed of rotation to a maximum that is commensurate with the amount of unbalance. This feature of speed control is realized by arranging the motor mount so as to make belt tension directly responsive to the movement of unitary assembly 40. p Belt tension determines the value of the driving torque transmited from the motor to lthe rotating basket and a decrease in the tension results in a decrease in torque transmitted.
Movable motor mount 45 is therefore linked with leg 18 of unitary assembly 40 by cable 53. A turnbuckle 54 is provided in cable 53 for maintaining proper ajustment of tension between uniary assembly and motor 33. Also attached to movable motor mount is dashpot 55 of conventional design in which deformable plunger 58 and back-up plate 57 cooperate to offer relatively low resistance in the direction of axial movement to the left and relatively large resistance to axial movement in the opposite direction. During axial movement of shaft 59 to the left in FIGURE 2, plunger 58 is deformed by the pressure of the uid within dashpot 55. This deformation permits the fluid to flow easily past plunger 58 and allows shaft 59 to move more easily to the left. During the return movement to the right, however, plunger 58 is backed up by plate 57 and thus not deformed and the ow of fluid past plunger 58 is limited to a slow rate for preventing rapid movement of shaft 59. Dashpot 55 is maintained in a relatively xed relationship to base frame 10 by bracket or cradle 56 which is suitably attached to base frame 10.
It may thus be seen that the driving system is directly responsive to movements of the unitary assembly caused by unbalanced loads contained therein for maintaining the speed of rotation at a maximum value dependent upon y the amount of unbalance contained within the spinning basket. As seen in FIGURE 1, pivotal movement of the unitary assembly 40 to the left produces a pull on cable 53 causing the motor 33 and movable motor mount 45 to also move to the left as viewed in FIGURE 2. This movement reduces the amount of tension in drive belt 30 to allow pulley 31 to slip with respect to `drive belt 30.
Movement of the motor and the motor mo'unt 45 to the left causes plunger 58 carried by shaft 459 toy move within dashpot 55 lin a direction to which little resistance iis offered. Since there is greater resistance to movement of plunger 58 in the opposite direction, there is thus inserted a time delay in the return movement of motor mount. 45. It is lseen that without use of the dashpot 55, there would 'be rapid engagement and disengagement of pulley `311 with belt 30 -as the motor is moved t-o the left and then released as a `result of the oscillating mon/ement of the unitary assembly 40. Under sfueh circumstances, disengagement would be dependent on both magnitude and frequency of vibration; however, the fu-se of -a properly designed dashpot provides a means for limiting response to conditions of magnitude only.
Referring now to FIGURE 3, an alternate embodiment of the present invention will be described. This embodiment describes the operation of the speed control system as adapted for controlling a horizontal axis washing machine such as' the washer-drier combination o-f FIGURE 3. A combination washer-drier olf this tyspe is described in detail in U.S. 3,040,440, to J. C. Mellinger et al., issued June 26, 1962.
Briefly, the combination washer-drier Iunit shown includes a substantially flat surfaced base iframe mounted on legs 811. Mounted on base `fra-me 80 are two support members, such as support 83, which are welded or securely iaflxed in some suitalble manner to base Iframe 80 in spaced relationship to serve as the two major supports for the washer-drier unit illustrated in FIGURE 3. The support members z83 are of a channel-like cross section, generally rectangular in elevational configuration `and adapted to receive pivot pins, such as pin 84. Attached to tub or casing 85 are two tub brackets, such as bracket 86, which are journalled on pins 84. This allows the tub 85 to oscillate back 4and forth on the pivot pins in lan arcuate movement in response to various forces generated within that tub.
rIub 85 is maintained in an upright position on pivot pins 84 by two centering springs 88 connected between tub '85 and base frame 80. Also attached to dnum or tub 85 is a damper leaf spring 89 carrying a damper pad 90 in a ball and socket joint at the end of damper spring 89. Attached to base frame 80 is an upstanding damper plate 91 which is engaged by damper pad 90 to absorb and dissipate the energy imparted to the tuby 85.
It will be seen in FIGURE `3 that tub 85 includes a generally cylindrical side wall 93 and a pair of spaced rear walls 94 and 95. Contained Within tub 85 is a perfor-ate clot-hes receptacle or Abasket 96 which is affixed to drive shaft 98 for rotation therewith.
The power to rotate basket 96 through Ithe lange pulley 99 atiixed to drive shaft 98 is supplied by a single speed mot-or 100. The output sharft `of motor 100 is connected to a exible coupling (not shown) which is connected in turn tothe input shaft of transmission 103. Motor 100 and transmission 103 are lattached to the lower portion of tub 85 by means of bracket 101 which is movable yfor maintaining proper `adjustment of motor 100 and transmission 103 with respect to drum 85.
Transmission 103 is operable as a twoaspeed transmission unit and is provided with an output pulley 104 in Iturn drivabl-y connected to the large drive pulley 99 through belt 105. Transmission l103 is operable upon energization of ysolenoid 106, controlled by a time mechanism l(not shown), to cause clothes receptacle 95 to be rotated at a speed of approximately 300 revolutions per minute while deenergization of solenoid 106 allows transmission 103r to drive receptacle 96 to tumble contents contained therein at approximately 50 revolutions per minute.
Also driven by transmission 103 is pulley 108 which is connected to fan pulley 109 through the belt 110 from driving fan pulley 109 at a speed approximately equal to that olf motor 100. Motor 100 also drives pump l111 through belt 113.
Mounted on bnacket 101 is lbelt tension control linkage 114 which pivots about pivot pin 115 carried by bracket 101. Tension control linkage 114 carries idler pulley 1.16 at the extremity of ann 118 yfor engaging belt 105 to Amaintain proper belt tension for driving between output pulley 104 and main drum pulley 99. Linkage 114 is biased in a clockwise ldirection about pivot 115 by spring 1=19 which is connected between arm 120 of linkage 114 and brackets 12.1 `secured to wall 95 of drum 85.
Also forming a par-t of tension control linkage 114 is depending leg 123 which carries roller or wheel 1-24 at its lower extremity. Leg 123 is provided with adjustment means 125 for `adjusting its over-all length so as to 'insure proper engagement of roller 124 'with base frame 80.
Attached at pivot point 126 on arm 120 of linkage 1114 is dashpot 128. Dashpot 128 includes shaft 129 which moves `a plunger within dashpot 128 relatively easy in only one direction of 4axial movement similar in action to the dashpot 55 of FIGURE 2. Dashpot 128 is xed to bracket 131 at pivot point 130 thus maintaining dashpot 1.28 is a relatively xed position with respect to drum 85, while allowing axial movement of shaft 1129 as linkage 114 pivots about pin 115.
It may be heen in FIGURE 3 that tension control linkage 114r is thtus `respon-sive to arcuate movements of tub 85 for controlling belt tension of drive belt 105.
As tub `85 moves to the left in an arcuate manner due to unbalanced spinning loads within basket 96 during extraction operations, pivot pin 115 will move closer to base frame 80. As movement ocurs, the engagement -o-f roller 124 with base iframe 80 will tend to pivot control linkage 114 in `a counterclockwise direction about .pivot pin 115 thus tending to move idler pulley 116 away :from belt 105 for reducing the amount of tension on the belt between transmission pulley 104 and drum pulley 99. This reduction in tension will cause pulley 104 to slip relative to belt 105 for at least partially disconnecting the drive power lto drum pulley 99 for preventing further acceleration. The amount of disconnection Ibetween pulley 104 Iand belt 105 is, of course, dependent upon the movement of :pulley 1.16 which, in turn, is dependent upon the magnitude of movement of tub and thus .a function of the amount of unbalance in the spinning basket.
The counterclockwise movement of linkage 114 will also tend to act-uate movement of plunger 129 of dashpot 128 in a direction of little resistance to movement. Operation of dashpot 128 in the return direction offers relatively large resistance to movement and tends to maintain idler pulley 116 :at lleast partially disengaged for a longer period of time. Thus a time delay is realized before allowing idler pulley 116 to become re-engaged with belt 105.
It is thus seen that the counterclockwise movement of tension control linkage 114 efected by engagement of roller 124 4with base frame 80 :and the cooperating operation of dashpot 128 will maintain the driving connection between pulley 104 `and drum pulley 99 in a condition to maintain the rotation of basket 96 at a maximum speed commensurate with the magnitude of arcuate movement which in turn is a function of the amount of unbalance contained within basket 96.
Further embodiments would include utilizing a hydraulic system for effecting a change in belt tension. Such a system could include a cylinder and piston or bellows arrangement responsive to movement of the washing container for feeding iluid to a iluid responsive device mounted so as to decrease belt tension in response to movement of the clothes container. 'I'he feed line connecting the fluid device could, of course, include a valve device |for restricting flow in one direction so as to provide a time delay in the control system.
Additio-nal embodiments would be possible by adapting the unbalance sensing system of the horizontal axis m-achine to the vertical axis machine rand vice versa.
Still additional embodiments of the present invention would be available with extractors and washing machines in which alternate mountings and arrangements of the drive system make possible further variations in the means for making belt engagement responsive to movement o-f the container when rotating with an unbalanced load.
It may thus be seen from the foregoing description that the present invention provides a novel speed -control system for assuring optimum extraction operation by allowing extraction at a maximum speed commensurate with the -amount of unbalanced loading in the spinning container While assuring elimination of undesirable excessive vibrations. The direct control of belt tension for limting driving torque is a simple, relatively inexpensive and easily manufactured system, yet effective for providing an irnproved mode of operation.
In the drawings and specification, there has been set forth a preferred embodiment of the invention and, although specic terms are employed, these are used in a generic and descriptive sense only, and not for purposes of limitation. Changes in form and the proportion of parts, as well as the substitution of equivalents are contemplated, 4as circumstances may suggest or render expedient, without departing from the spirit, or scope, of the invention as further defined in the following claims.
1. In 'a centrifugal extractor, the combination comprising: a revoluble container provided with an Iaccess opening; a frame member; means for supporting said container on said frame member to permit relative movement thereto; drive means including motor means for rotating said container at extraction speeds, said drive means further including belt means drivingly connecting said motor means to said revoluble -container to transmit a predetermined driving torque to said container; means for maintaining a predetermined |belt tension to effect rotation of said revoluble container at extraction speeds; means responsive to movements of said container due to unbalanced loading therein for at least partially disenga-ging said belt means to decrease belt tension; and means for retarding re-engagement of said belt means to limit transmission of said driving torque and to effect rotation, of said container at a speed commensurate with said movements.
2. In a centrifugal extractor, the combination comprising: a revoluble container provided with 'an access opening; a `frame member; means for supporting said container on said frame member to permit relative movement thereto; drive means including motor means for rotating said container at extraction speeds, said drive means further including belt means for transmitting driving torque from said motor means to said revoluble container; biasing means for maintaining a predetermined tension of said belt means; and means responsive to` movements of said container due to lunbalance loading therein for opposing operation of said biasing means and maintaining belt tension at less than said predetermined tension to limit transmission of said driving torque and to effect rotation of said container at a speed commensurate with said movements.
3. In a centrifugal extractor, the combination comprising: a revoluble container provided with an access opening; a frame member; means for supporting said container on said frame member to permit relative movement thereto; drive means including motor means; said drive means further including belt means connecting said motor means and said revoluble container to transmit torque for accelerating said container to an extraction speed; biasing means for maintaining a predetermined tension on said belt means to effect engagement of said belt means and said motor means for transmitting a predetermined torque; means responsive to movements of said container due to unbalanced loading therein for opposing operation of said biasing means and for decreasing said belt tension to effect at |least partial disengagement of said belt means from said motor means; and time delay means for controlling re-engagement of said belt means to limit further rotational acceleration of said container commensurate With said movements.
4. In a centrifugal extractor, the combination comprising: a revoluble container provided with an access opening; a frame member; means for -supporting said container on said frame member to permit relative movement thereto; Idrive means including motor means and be'lt means, said drive means also including biasing means for maintaining a predetermined belt tension to transmit torque for rotating said lrevoluble container at ext-raction spec-ds; means responsive t-o movements of said container due to unbalanced loading therein :for decreasing said belt tension and maintaining the tension at less than said predetermined tension t-o limit transmission of said driving torque an-d to effect rotation lof Isaid container at a speed commensurate with said movements.
5. In a Washing machine having a cycle of operations including at lleast one extraction operation, the combination comprising: a revoluble container provided with an access opening, a frame member; means for supporting `said container on said framelmember, said supporting meansrjbeing constructed and disposed to permit relative 14vementbetween said container and said Aframe memrive means including motor means and belt means;
yi'neans for maintaining 'a predetermined belt tension to effect rotation of said revoluble container at extraction speeds; means responsive to movements of said container due to unbalanced :loading therein 'for decreasing said belt tension; and means for maintaining lbelt tension at less than said predetermined tension for limiting maximum rotational speed of said container to a speed commensurate with the imbalance loading causing said movement.
6. In a Washing machine having a cycle `of operations including at least one extraction operation, t-he combination comprising: a container revoluble about a vertical axis and provided with an acces-s opening; a frame member; means for supporting said container on -said frame member in a substantially vertical posit-ion, said supporting means being constructed and disposed to permit nutational movement of said container with reference to said frame member when said container is rotating with an unbalanced load; drive means including motor means for rotating said revoluble container at extraction speeds; said Vdrive means 'further having belt means drivingly connecting sai-d drive means to said :revoluble container; means 4responsive t-o movements of said container due to unba'lance load-ing therein to effect .at least partial disengagement of said belt means; and time delay means retarding re-en-gaigement of said belt means to limit the rotational speed of said container to a maximum commensurate with unbalanced |loading therein.
7. In a washing machine having a cycle of operations including at least one extraction operation, the combination comprising: a container revoluble about a non-vertical axis provided with an -access opening; a frame member; means for supporting said container on said frame member, said supporting means lbeing -constructed and disposed to permit arcuate movement of said container relative to said 'frame member when said container is rotating with an unbalanced load; `drive means including motor means for rotating said revoluble container to extract fluid from materials contained therein; said drive means having belt means drivingly connecting said motor means to said revoluble container; means responsive to movements of said container due to unbalanced loading therein to effect at least partial disengagement of said belt means; and time delay means controlling re-engagement of said belt means to limit the rotational speedof said container to a maxim-um commensurate With unbalanced loa-ding therein.
8. In a washing machine having a cycle of operati-ons including at lleast one extraction operation, the combination comprising: a revoluble container provided with an access opening; a frame member; means lfor supporting said container on said frame member for rotation in a substantially vertical position, said supporting means being constructed and disposed to permit nutational movement of said container 'with reference to saidframe member when said container i-s rotating With an unbalanced load; drive means including motor means and belt means for rotating said revoluble container at extraction speeds; said drive means further including biasing means` for maintaining proper engagement o-f said motor means with said belt means; linkage means connected between Isaid supporting means and said motor means and operative for at least partially disengaging said motor means from said belt means in response to movements of said container duel to unbalanced loading'therein; and time delay mea-ns for opposing operation of said biasing means and retarding re-engagement of said drive means With said belt means to limit the rotational speeds of said container to a maximum commensurate with the move-4 ments of said container.
9. In a washing machine Ihaving a cycle of operations including at least one extractable operation, the combination comprising: a revoluble container provided with an access opening; a frame member; means for supporting Said GODlaiIlGr ou Said frame member for rotation about a non-vertical axis; said rsupporting means ybeing oonvstrueted and disposed to permit arcuate movement of said `container relative to said base `frame when said container is rotating with an unbalanced load; drive Imeans including motor means and belt means -for rotating `said revoluble container at extraction speeds; 'belt tensioning means for maintaining said belt means operatively engaged with said motor means; means connected to said tensioning means and responsive to said arcuate movements for -at least partially disengaging said belt means from said motor means; and time delay means for opposing operation of said belt tensioning means and retarding re-engagement of said belt means with said motor l 0 means to llimit the rotational speed of said container t0 a maximum commensurate with movements of said container.
References Cited by the Examiner UNITED STATES PATENTS 1,893,038 l/l933 Schenck 210-144 X 2,950,009 8/1960 Bochan 210-144 X 3,014,590 12/1961 Metzger 210-144 X 3,068,677 12/1962 Buss 68-24 REUBEN FRIEDMAN, Primary Examiner.
D. M. RIESS, Assistant Examiner.