US2780086A - Time delay switch - Google Patents

Description

Feb. 5, 1957 c. M. DUNLAP TIME DELAY SWITCH 2 Sheets-Sheet 1 Filed Dec. 10, 1954 PUMP VALVE SOLENOID INVENTOR' CHARLES M. DUNLAP BY ATTORNEYS Feb. 5, 1957 c. M. DUNLAP TIME DELAY SWITCH 2 Sheets-Sheet 2 Filed Dec. 10, 1954 a MW INVENTOR. CHARLES M. DUNLAP ATTORNEYS TIME DELAY SWITCH Charles IV. Dunlap, Mansfield, Ghio Application December 10, 1954, Serial No. 474,493

18 (Ilaims. (Cl. 68--24) This invention relates to time delay switches, and particularly to switching or controlling mechanism for causing a rotating member to be driven at low speed after a period of high speed operation under conditions of excessive vibration and to thereafter reestablish high speed drive in response to a predetermined amount of rotation of the member at low speed.

The invention relates particularly to a control switch mechanism for automatic washing machines having a spin dry cycle during which water is removed from the clothes by a centrifuging step. it often happens that the clothes in the machine are not evenly distributed in the rotor at the commencement of the centrifuging cycle and thus unduly large vibrations are induced in the machine. If. the magnitude of the vibrations exceeds a certain predetermined value, there is danger of damage to the machine and it is therefore desirable to discontinue the centrifuging cycle and to rotate the rotor at low speed until the clothes have redistributed themselves in such a way that centrifuging may be continued without excessive vibrations.

in general, the invention is embodied in a control switch mechanism mounted adjacent a part of the rotor, particularly a tub resiliently mounted in the machine housing and enclosing the rotor basket. The control mechanism includes a rotary element normally set in a fixed position but subject to excessive vibrations between the tub and housing to partially rotate the element with resultant translation thereof. Translation of the element causes a switching mechanism to establish low speed drive to the rotor or basket of the washing machine and that same translation places the rotary element in position to be engaged by the rotor of the machine and rotated thereby in a step-by-step manner to effect translation back to its original position wherein high speed drive to the rotor is again established. In addition to the specific construction, the principal feature of this invention resides in the arrangement wherein the rotor or basket itself, being driven at low speed, constitutes the timing mechanism for reestablishing high speed drive after the basket has made enough revolutions at low speed to effect redistribution of the clothes therein.

It is therefore an object of this invention to provide a control mechanism that is economical to produce and highly eflicient and reliable in operation.

A further object of this invention is to provide a control mechanism having a timing feature but wherein no separate timing" device is employed.

it is still another object of this invention to provide a control mechanism for a washing machine that is effective in response to excessive vibrations during a centrifuging cycle, to establish low speed drive to the machine basket and to thereafter be responsive to rotation of the basket a predetermined amount to again establish high speed drive for centrifuging.

Further and additional objects and advantages will become apparent to those skilled in the art as the descripte States atent 0 Id tion proceeds in connection with the accompanying drawings, wherein:

Fig. l is a vertical sectional view through a washing machine embodying the present invention;

Fig. 2 is a vertical sectional view taken substantially along the line 2-2 of Fig. 1;

Fig. 3 is a fragmentary sectional view on an enlarged scale, taken substantially along the line 33 of Fig. 2;

Fig. 4 is a vertical sectional view taken substantially along the line 44 of Pig. 3;

Fig. 5 is a vertical sectional view taken substantially along the line 55 of Fig. 4;

Fig. 6 is a schematic wiring diagram illustrating one possible circuit arrangement incorporating the present invention; and

Pi g. 7 is a fragmentary view of a portion of the mechanism of Fig. 4 but illustrating a modified form of pawl.

The present invention is particularly applicable to washing machines and an automatic washing machine is shown and described herein, but it is to be understood that the invention may be applied to other mechanisms also.

The washing machine shown in Figs. 1 and 2 comprises an outer housing 2 which may be supported on suitable feet 4 and which is provided with an access door 6. An imperforate tub 8 is mounted in the housing 2 by means of a resilient supporting arrangement indicated generally at it and tension springs 12. The supporting arrangement ll? is of conventional construction and need not be further described in detail except to say that it sup ports the major portion of the weight of the machine mechanism but permits vibration of the tub 3 about an axis generally in the arrangement ill. The tension springs 12 partially support the weight of the tub and related mechanism and are effective to normally hold the tub in a centralized position. Suitable bellows or other sealing means 14 provide a water-tight seal between a central opening 16 in the front wall of a tub 8 and the access doorway in the housing 2. The bellows 14 effect the desired sealing without interfering with vibratory movements of the tub.

A suitable drive motor 18 is mounted on the tub 8 and drives, through a drive pulley 20 and belt 22, to a sheave or pulley 24 secured to shaft 26. The shaft 26 is journalled in suitable bearin s 28 carried by the tub 8 and rotary basket 30 is fixed to the inner end of the shaft 26 within the tub 8. The basket 39 is provided with an access opening 32 in alignment with the opening 16 in tub 8 and the access door 6 of the housing 2. The motor 18 includes a housing 34 in which a suitable variable transmission is mounted to effect different speed drives from the motor to the basket Ell. The gearing in the housing 34 and the controls therefor are conventional and need not be further described. The motor 18 also includes an integral pump 36 for pumping water from the tub 8.

Fig. 6 schematically indicates a wiring diagram wherein switches 38 are cam-actuated by a motor driven cam (not shown) to sequentially effect the usual cycles of operation common to automatic washing machines; The water switch is of a conventional type actuated by air pressure bellows and connected by a tube to the tub sump. When the tub is being filled, the switch is actuated by the pressure of the head of water. It resets when the pump 36 relieves the pressure. Such switches and their use in washing machines are well known and will not be further described.

The drive from the motor 13 to the rotor or basket 30 is at a speed determined by the condition of solenoid 40. When solenoid 49 is energized, the variable transmission in housing 34 is actuated to establish a high speed drive to the basket to spin the clothes therein and extract most of the moisture by centrifugal force. When the solenoid is deenergized, the transmission normally returns to the low speed drive utilized during the Washing cyole. The time delay switch 42 controls energization .of the solenoid 40 and the means for actuating switch 42 constitute the means of the present invention.

The washing machine construction and the general features of the control circuit therefor are conventional in the art and donot constitute part of the present invention.

'It'is tobe understood that any equivalent washing machine'structure or circuit arrangement may be employed with equal facility.

The switch 42 is shown in greater detail in Figs. 1 through 5 and consists of a pair of spring arms 44 mounted at one end on a bracket 46 secured to the rear wall of the tub 8. The arms 44 are insulated from each other and from the bracket 46 by insulating material 47 (Fig. 4). Each of the arms 44 is suitably connected to conductors 48 and 50, respectively, constituting part of the wiring circuit shown in Fig. 6. Adjacent their free ends the arms 44 carry contact elements 52 and the arrangement is such that the arms 44 normally tend to assume a posi'tion wherein the contacts 52 are separated, thus deenergizing solenoid 40. As stated, the arms are resilient and their free ends may be displaced as shown in Fig. 4

'to a'position wherein the contacts 52 engage each other to energize the solenoid 40.

A spring arm 54 is mounted at one end thereof to the flange 56 of bracket 46 whereby the arm 54 constitutes a resilient cantilever support for a cam disc 58. The arm 54 is further provided with an insulated projection or boss 60 arranged adjacent the outer ends of the switch arms 44. The spring arm 54 is normally biased in an upward direction so that it normally tends to move upwardly to permit contacts 52 to separate and open the solenoid circuit. The spring arm 54 is bifurcated (see Fig. 3) to provide arms 62 which are formed at their outer ends as loops 64 constituting bearings for the ends of a shaft 66 to which the cam disc 58 is rigidly secured. The cam disc 58 is provided with a generally circular periphery, the major portion of which is truly circular and concentric to the shaft 66 but which is provided with a single lobe 68 of limited angular extent and projecting outwardly from the circular periphery by an amount at least: equal to the amount of movement'necessary to be imparted to the outermost end of arm 54 to effect opening and'icilosing of switch 42.

The rear wall of the tub 8 has a further bracket 70 fixed thereon and which has an outwardly extending flange 72 projecting outwardly over'the periphery of the cam 58. The bracket 70 is so positioned that the resilient characteristics of the arm 54 hold the periphery of cam disc 58 in contact with the lower. face of flange 72 at all'times. The parts are so proportioned and positioned that when the cam disc 58 is in the full line position of Fig. 4 with the tip of its lobe 68 engaging flange 72, the arm'54 is pushed downwardly far'enough to effect closing of switch 42. When the cam disc 58 is rotated through asmafll angle to remove its lobe 68 from contact with the'flange 72, and permit the circular portion of the cam periphery to engage that flange, the arm '54 is permitted to move upwardly to the dotted line position of Fig. 4 to open the switch 42.

The cam disc 58 is further provided with laterally extending ears 74. The ears 74 are angularly spaced about the shaft.66 and, in the form sh0wn,tsix such ears are provided. The ears 74 extend laterally of the disc 58 inwardly of the cam periphery thereof.

The housing 2 supports a bracket 76 having an inwardly extending flange 78 extending inwardly to a position in line with the lowermost ear 74 of the cam disc but laterally displaced thereof in a direction parallel to the rear wall of the housing 2. Figs. 3 and 4 clearly show the relationship thus described. The parts are so positioned 8 does not vibrate suflicienttly to engage the lowermost ear 74 with the edge of flange '78. In the event the clothes in the basket 30 are so unevenly distributed that centrifuging operation causes excessive vibration of the tub 8, the tub and, therefore, disc 58 which is mounted thereon, will move laterally a sufficient distance to not only engage the lowermost ear 74 with the adjacent edge of flange 78, but to move a sufiiciently greater distance to cause the flange 78 to rotate the cam 58 from the dead-center full line position shown in Fig. 4 so that the force of the biased spring 54 holding the cam lobe 68 against flange 72 is exerted on the slope of the lobe, thus rotating the cam 58 to the dotted line'position. Thus, excessive vibratory movement of the tub 8 will cause the switch 42 to open the drive from motor 18 to the basket 30 will, as a result, be reduced from the high speed drive to a relatively low speed. During the low speed drive, the clothes in basket 30 may tumble and redistribute themselves in a more uniform arrangement. As shown, the bracket 76 is mounted on the housing 2 by means of bolts or screws 77 passing through slots 79 in bracket 76 whereby the bracket may be adjusted to the desired position.

A bracket 80 (see also Fig. 5) mounted on the inner face of the sheave 24 is provided with a pawl 82 pivoted thereto on an axis 84. A spring 86 is secured to the bracket 80 by suitable means such as bolts 88 and engages an upwardly extending finger 90 of the pawl 82 to hold that finger against vertical flange 92 of bracket 89. The lowermost portion of the pawl 82 comprises a finger 94 extending downwardly and forwardly from the axis 84. The pawl 82 may 'thus be rotated from the normal position shown to a position wherein the rearmost edge 96 of finger 94 engages the flange 92 with the lower arm of the pawl extending downwardly in the position indicated by dot-ted lines in Fig. 4. The dotted line are A indicates the path of travel of the tip of pawl 82 when in its normal position shown, whereas the dotted are 8 indicates the path of travel of the tip of the pawl 82 when swung about its axis 84 to the dotted line position. As is clearly evident from Fig. 4, when the cam disc 58 is in position with its lobe 68 bearing against the fixed flange 72 of bracket 70, the cam disc itself is pushed down against the action of spring arm 54 to such position that its cars 74 lie outside the are A. Thus, the sheave 24 and the basket 30 may rotate continuously without the pawl 82 engaging the ears 74 as long as the cam disc remains in the described position. When excessive vibra tions cause the flange 73 to partially rotate the cam disc 58, the ear 74 shown in full line at C will be moved to the dotted line position C wherein its upper edge crosses the are A in position to be engaged by the tip of pawl 82. When pawl 82 engages the ear in position C the pawl is swungiabout its axis 84 to the dotted line position and is effective to push the ear at C to about the position identified'at D whereupon the tip of the. pawl passes oif the upper edge'of the ear 74 near position D after having rotated the cam disc through a portion of one complete rotation. During this interval the circular portion of the cam periphery remains in contact with the flange 72 and the next succeeding ear '74 also extends across the are A to be engaged by the pawl 82 after the basket has made another revolution at low speed. Thus, the low speed rotation of the sheave 24 will cause the cam disc 58 to rotate in a step-by-step manner until its lobe 68 is again brought into contact with flange 72, at which time the cam disc will be pushed downwardly to such an extent that its cars 74 lie outside the are A and no further rotation is impanted thereto by'the pawl 82. At the same time the spring arm 54 is pushed downwardly and closes switch 42 to re-establish high speed drive to the basket. In the form shown, the basket 30 must rotate through six complete revolutions at low speed beforehigh speed is re-established and in that time the {:3 u clothes 'will have redistributed themselves. The illustrated embodiment, however, is merely illustrative of the invention and it may be found in many instances that only six complete revolutions of the basket 30 at low speed are not sufiicient to redistribute the clothes, in which event it is contemplated that a greater number of ears 74, or their equivalents, be provided so that the basket rotates a greater number of times before high speed operation is re-established.

In some instances the basket 8 and its contained clothes may be of such weight and inertia and/ or may be operated at such high speed during the centrifuging cycle that the mere opening of the contacts 52 and re-establishment of low speed drive will not in itself immediately reduce the speed of rotation of the basket 8. In such instances the inertia of the basket and its contents cause it to continue rotating at high speed for an appreciable length of time after cam 58 is moved to the dotted line position of Fig. 4, during which time the sheave 24 may make several complete turns. pawl 82 would advance the cam 58 and high speed drive could thus be re-established even before the basket 8 slows down to a low enough speed to redistribute the clothes. In such cases the modified pawl construction shown in Fig. 7 may be employed.

In Fig. 7, elements identical to those shown in Fig. 4 are identified by the same reference characters. The bracket 80 of Fig. 7 is the same as bracket 89 of Fig. 4 except that its flange 92' is provided with a slot or opening 1 30. The lowermost end of the slot 100 terminates above the lower end of flange 92, the lower part of which defines a stop abutment 102. The pawl 104 is pivoted to bracket 80' at 84 with it plane of pivotal movement extending through slot 100. The forward edge of pawl 104 is formed with two surfaces 106 and 108 angul-arly arranged to define a notch or depression having its apex generally opposite the pivot 84. Spring 86 is biased to normally urge its free end toward the pivot 84 into engagement with both surfaces 136 and 108, as shown in full lines in Fig. 7, and thereby normally hold pawl 104 with its outermost end lying on are A. The innermost part of pawl 104 extends through slot 100 and is formed to define a relatively heavy weight element 110 rearwardly of pivot 34. The element 110 is further formed with an abutment surface 112. Thus, pawl 104 may rotate counterclockwise (as seen in Fig. 7) until its abutment urface 112 engages stop abutment 102, as indicated by dotted outline B, such rotation being opposed by the end of spring 86 acting on surface 106. The pawl 194 may also be rotated clockwise from the full line position of Fig. 7 to dotted line position F with its rear edge engaging abutment stop 102 and its outermost tip lying on are B.

The strength of spring 86 and the weight of element 110 are so related that centrifugal force acting on weight 110 rotates pawl M4 to the position shown at B when sheave 24 rotates at speeds above a predetermined value. Preferably that predetermined speed is approximately the low speed of the machine or only a little above that speed.

At the start of a centrifuging cycle, the pawl 104 pivots to the position at E (Fig. 7) with its outer end positioned inwardly of are A a distance such that the pawl will not engage ears 74 of cam 58 even if the cam is moved to the dotted line position of Fig. 4 by excessive vibration of the basket and the pawl remains in that position as long as the basket 8 continues to rotate at high speed. When the basket slows down to a speed approaching its low speed, spring 86 will overcome the centrifugal force on weight 11% and rotate pawl 1M back to the full line position of Fig. 7 where its outer end is on are A and in position to engage the ears 74 of disc 58. Upon each engagement of the pawl 104 with an ear 74, the pawl moves to position F to advance cam disc 58 one step and then spring 86 returns it to the full line position of Fig. 7, which corresponds to the full line position At each such turn the L 6 of pawl 82 of Fig. 4. Thus, the step-by-step resetting of cam disc 58 does not start until the basket slows down to a low speed and ample time is provided for redistribution of the clothes before high speed drive is again established.

The specific embodiment-s shown and described herein are merely illustrative of the invention, which is not limited thereto. It is to be understood that many other modifications may be resorted to within the scope of the appended claims.

l claim:

l. in a device of the class described; a frame, a rotary member, neans supporting said rotary member for rotation thereon, said supporting means being mounted on said frame for movement relative thereto in response to rotational unbalance of said rotary member, drive means for rotatin said rotary member, control means for said drive means for effecting either hi h speed or low speed rotation of said rotary member, a switch for actuating said control means, a switch-operating member movably mounted on said supporting means for movement to a first position wherein said switch is operated to establish high speed drive and to a second position wherein said switch is operated to establish low speed drive, means responsive to movement of predetermined magnitude of said supporting means relative to said frame during high speed drive for moving said switch-operating member to said second position, and movable means arranged to be moved by rotary motion of said rotary member a predetermined amount at low speed for moving said switchoperating member to said first position.

2. A device as set forth in claim 1 wherein said switchoperating member comprises a rotary element having projections thereon, one of said projections being engageable with means fixed on said frame for moving said switch-operating member from said first position toward said second position.

3. A device as set forth in claim 1 wherein said switchoperating member comprises a rotary element having projections thereon, one of said projections being engageable with means fixed on said frame for moving said switch-operating member from said first position toward said second position, and a pawl on said rotary member engageable with said projections successively when said rotary element is in said second position to rotate said rotary element and move said switch-operating member back to said first position.

4. in a. machine having a frame, a rotary member, supporting means movably mounted on said frame and rotatably supporting said rotary member, drive means for rotating said rotary member, and control means for said drive means for establishing either high speed or low speed rotation of said rotary member; the improvement comprising: a switch on said supporting means for actuating said control means, a rotary cam mounted for rotation and translation on said supporting means, said cam engaging a portion of said supporting means whereby rotation of said cam produces translation thereof between a first and second position thereof, means responsive to translation of said cam for opening and closing said switch, means on said frame engageable with a portion of said cam for rotating said cam sufficiently to effect translation thereof from said first position toward said second position in response to a predetermined movement of said supporting means relative to said frame, and means carried by said rotary member engageable with said cam when said cam is in said second position and operable in response to a predetermined rotation of said rotary member to further rotate said cam to effect translation thereof back to said first position.

3'. A machine as defined in claim 4 wherein said cam is provided with angularly spaced projections and wherein said means carried by said rotary member comprises a pawl movable along a circular path spaced from said projections when said cam is in said first position but 7 engageable with said projections to rotate said cam when said cam is in said second position.

6. A mechanism having a support, a member rotatably mounted on said support, drive means for rotating said member, control means for said drive means mounted on said support, said control means being effective, when actuated to a first condition, to establish a high speed drive to said member and, when actuated to a second condition, to establish a lower speed drive to said member, a control element, means mounting said control element for rotation and translation on said sup port, means responsive to rotation of said control element to efiect translation thereof between a first and second position, means responsive to movement of said element to said first position for actuating said control means to said first condition and responsive to movement of said element to said second position for actuating said control means to said second condition, means normally biasing said control element to said first position, means responsive to a predetermined magnitude of rotational vibration of said member for rotating said element to efiect translation'thereof from said first to said second position, and restoring means driven by siad member to further rotate said element to eit'ect translation thereof back to said first position.

7. in a washing machine or the like having a housing, a tub mounted in said housing for vibratory movement therein, a rotor journalled in said tub, drive means for rotating said rotor at either high or low speed, movable control means for said drive means movable in response to excessive vibratory movement of said tub when said rotor is driven at high speed for establishing low speed drive from said drive means to said rotor, and means rendering said control means thereafter movable in response to rotation of said rotor to reestablish high speed drive thereto after a predetermined amount of rotation thereof at low speed.

8, A machine as defined in claim 7 wherein said rotor is provided with a restoring element rotatable therewith along a predetermined circular path and wherein said control means includes a device movably mounted on said tub for movement between a low-speed position adjacent said path and a high-speed position remote from said path, said device having means thereon positioned in the circular path of said restoring element when said element is in said low-speed position and arranged to be moved by said restoring element to said high-speed position wherein said last-named means is removed from said path.

9. A machine as defined in claim 8 including a fixed element on said housing engageable with said last-named means upon excessive vibration of said tub to move said device to said low-speed position.

10. A control switch mechanism for the drive means ofa machine having a rotor journalled on a support and drive means for rotating said rotor at different speeds, said switch mechanism comprising; a spring arm mounted at one end on said support, a cam disc journalleo on the other end of said arm, said cam disc being of uniform radius throughout the major portion of its periphery an having aperipheral undulation of limited angular extent, a fixed abutment on said support, said spring arm being biased to hold the periphery of said cam disc against said abutment, a plurality of angular-1y spaced projections extending laterally from said disc, a pawl carried by said rotor for rotation therewith along a path adjacent said disc, at least one of said projections lying in said path when the portion of said cam disc periphery oi uniform radius is in engagement with said abutment, the radial extent of said undulation being such that all said projections are removed from said path when said undulation engages said abutment, and a control switch actuable by movement of said spring arm in response to rotation of said cam disc.

11. A control switch mechanism as defined in claim 10 wherein said undulation is a lobe of greater radius than the major portion of said disc periphery and wherein said spring arm urges said disc in a direction toward said path.

12. A control switch mechanism as defined in claim 10 wherein said projections comprise tabs extending laterally from one side of said disc radially inwardly of the periphery thereof.

13. A control switch mechanism as defined in claim i0 wherein aid pawl is pivotally mounted on said rotor on axis eccentric to the rotor axis, stop means limiting pivotal movement of said pawl between first and second positions, the outermost end of said pawl being farthest from the axis of said rotor in said second position, and means norn ally biasing said pawl to said first position, the journal aAlS of said disc being substantially parallel to said rotor axis.

14. A control switch mechanism as defined in claim 12- including an element movable relatively to said support and into engagement with one of said projections to partially rotate said cam disc in response to excessive rotational vibration in said rotor.

15. A'rnachine as defined in claim 4 wherein said cam is provided with angularly spaced projections and wherein said means carried by said rotary member comprises a pa A l normally movable along a first circular path spaced from said projections when said cam is in said first position but engageable with said projections to rotate said cam when said cam is in said second position, and centrifugal means responsive to the speed of rotation of said rotary member and arranged to move said pawl on said rotary member, in response to high speed rotation thereof, to move along a second circular path spaced from said projections even when said cam is in said second position, and means cooperating with said centrifugal means for moving said pawl to said first circular path when said rotary member rotates at or below a predetermined low speed.

16. A control switch mechanism for the drive means of a machine having a rotor journalled on a support and drive means for rotating said rotor at different speeds, said switch mechanism comprising; a spring arm mounted at one end on said support, a cam disc journalied on the other end of said arm, said ca .1 disc being of uniform radius throughout the major portion of its periphery and having a peripheral undulation of limited angular ex tent, a fixed abutment on said support, said spring arm being biased to hold the periphery of said cam disc against said abutment, a plurality of angularly spaced projections extending laterally from said disc, a pawl pivotally mounted on said rotor, resilient means urging said pawl to a first pivotal position wherein one end thereof moves with said rotor along a first path adjacent said disc, at least one of said projections lying in said path when the portion of said cam disc periphery of uniform radius is in engagement with said abutment, the radial extent of said undulation being such that all said projections are removed from said path when said undulation enga es said abutment, a centrifugal weight on said pawl arranged to pivotally swing said pawl against the action of said resilient means, during rotation oi": said rotor above a predetermined speed, to position said one end of said pawl for movement along a second path spaced from said projections even when the portion of said cam disc of uniform radius is in engagement with said abutment, and a control switch actuable by movement of said spring arm in response to rotation of said cam disc.

17. A washing machine as defined in claim 7, including a centrifugally responsive element fixed relative to and rotatable with said rotor and arranged to render and maintain said controlmeans non-responsive to rotation of said rotor at rotor speeds above a predetermined value.

18. A control switch mechanism as defined in claim predetermined valve, the outermost end of said pawl being removed from said path when in said first position.

References Cited in the file of this patent UNITED STATES PATENTS Andrews et a1. Feb. 13, 1934 Hurley et a1 Feb. 16, 1943 Bassett Feb. 23, 1943

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