US3100030A

US3100030A - Brake mechanism for washing machine

Info

Publication number: US3100030A
Application number: US148616A
Authority: US
Inventors: Stephen L Mcmillan
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1961-10-30
Filing date: 1961-10-30
Publication date: 1963-08-06
Anticipated expiration: 1980-08-06

Description

Aug. 6, 1963 S. L. M MILLAN BRAKE MECHANISM FOR WASHING MACHINE Filed 001;. 50, 1961 3 Sheets-Sheet l INVENTOR. STEPHEN L. M MILLAN ATTORNEY Aug. 6, 1963 s. L. M MILLAN 3,100,030

BRAKE MECHANISM FOR WASHING MACHINE Filed Oct. 50, 1961 3 Sheets-Sheet 2 AGITATE INVENTOR. STEPHEN L. M MILLAN A 32 ATTORNEY Aug. 6, 1963 s. L. M MILLAN BRAKE MECHANISM FOR WASHING MACHINE 3 Sheets-Sheet 3 Filed Oct. 30, 1961 SPIN INVENTOR.

FIG. 7

ATTORNEY United States Patent 3,109,030 BRAKE MECHANISM FOR WASHING MACHHJE Stephen L. McMillan, Wheaten, 11., assignor to General Electric Qompany, a corporation of New York Filed Oct. 30, 1961, Ser. No. 148,616 6 Claims. (61. res-6s The present invention relates to brake mechanisms and more particularly to brake mechanisms for use on clothes washing machines.

It is generally known that with washing machines which operate on the principle of utilizing an inner vertical shaft for oscillating a centerpost agitator and an outer coaxial tubular shaft for rotating the spin basket, the basket has a tendency to oscillate sympathetically during agitation, a tendency Which disrupts the normal wash patterns. Various forms of mechanisms have been used to combat this tendency such as one-way spring clutches and solenoid-operated latching brakes. Of these mechanisms, the last-mentioned type has an inherent advantage in that it effects a second and equally important function, namely, that of stopping the basket rotation in a matter of seconds on occurrence of conditions such as de-energization of the motor. Such de-energization of the motor may be due to the termination of the spin period, may be due to the operation of safety switches incident to the lid of the machine having been opened, or may be due to the basket having gyrated excessively. In any event, it is most important that the spin basket be braked and stopped rapidly, this being of special urgency where the triggering condition was the opening of the lid by the user, in that the person opening the lid may intend to reach into the basket. This is a potentially dangerous situation, and an efficient basket braking mechanism is an effective protection against bodily harm.

In any event, when the motor is de-energized, a posi tive acting brake will quickly decelerate the basket and will hold the basket stationary at all times other than motor-spin periods. It is to improvements in this type of positive acting brakes that the present invention is directed.

With braking action of the type required, contact must be made between a stationary actuating mechanism and a braking device which is rotated with the spin basket but capable of rotation relative thereto. This contact must be transmuted into a relationship with the braking device (for example, a housing structure having an internally arranged brake band) which will cause the braking device to come to an immediate stop relative to the rotating basket and initiate the braking action to decelerate the rapidly rotating, high-inertia spin basket. The problems which result from this braking action are numerous. First, the stationary mechanism must latch into the rotating braking device on one rotation of the spin basket. With the basket rotating at a high speed, the possibility of losing the contact between the parts with consequent abrasion of the parts on one another is quite great. Following the lost contact, further contact must be made rapidly in order to initiate the braking action. Further, once the contact has been made, the high inertia of the rotor may tend to develop excessive strains in the latching members in attempting to halt the rotation of the device in too short a period of time. The present invention alleviates these difficulties by providing a stationary actuating member which seeks to establish a latching relationship with the rotating housing structure encompassing the brake band. The brake housing however ofiers only one area of limited angular extent where initial contact between the latch mechanism and brake band housing can be made. This initial contact is not an engaging contact in which the brake housing is attempted to be stopped. Instead,

3,100,030 Patented Aug. 6, 1963 there is a cam surface along which the latch mechanism must be conducted for a finite length of time before engagement is made with a portion of the housing. As this engagement is efiected, the brake band rotation is stopped and the spin tub is decelerated.

The latch mechanism is normally biased toward the plane of the initial contact area and cannot establish other than surface contact with the brake housing at any other angular position of the brake housing. This contact once established, is continued for over one half a revolution before the latching engagement with a radially extending brake arm is made. It is a feature of the invention that the brake arm is not in the plane of the contact area, and can only be reached by the travel of the latch along the cam surface. Thus, with a brake mechanism embodying the present invention, there is always a delay between the time of initial contact of the latch and the brake and the start of the braking action. By providing this time interval, it is ensured that the abrupt engagement which occurs at the start of braking happens only when a positive contact has been effected and ensured between the latch and the brake band housing portion.

To efiectuate this two-step brake engagement, the present invention utilizes a braking structure which includes a cylindrical brake band and outer housing about the spin shaft. Within the housing there is provided a latch contacting area of limited angular length extend-ing along the housing. From this area of contact, an acclivitous cam surface traverses the brake housing angularly for or more and terminates at a radial stop member spaced angularly and axially from the area of original contact. The stationary latch member is normally biased in the horizontal plane at the level of the contact area so that when the latch member is impelled toward the brake housing it can only contact the housing in the contact area. The member will enter the area and will slide along the cam surface as the housing continues its rotation for a finite time period. At the end of the period of positive con-tact the member engages said radially extending stop member to actuate the brake band bringing the braking structure to a stop and thus initiat ing the braking action between the brake band and the spin shaft.

It is therefore an object of the invention to provide an improved positive-acting, braking mechanism for a rotating clothes washing machine basket.

It is a further object of the invention to provide a brake mechanism which attains an initial contact between a stationary member and a rotating brake member at only one period in the rotation of the brake and eifec-ts the brwng action a finite period of time thereafter.

Other objects, features and advantages of the invention will be apparent from the detailed description of the presently preferred embodiments thereof, read in connection with the accompanying drawings in which:

FIG. 1 is a partially sectioned side elevational view of a washing machine employing the invention;

FIG. 2. is a top plan View partially in section of a first embodiment of the braking mechanism of FIG. 1;

FIG. 3 is a side elevational view of the first embodiment of the brake mechanism of FIG. 2;

FIG. 4 is a side sectional elevation viewed along the lines 4-4 of FIG. 2;

FIG. 5 is a top plan view partially in section of a second embodiment of brake mechanism;

FIG. 6 is a side sectional elevation of the second embodiment viewed along lines 66 of FIG. 5;

FIG. 7 is a cam development chart of the cam surface of the second embodiment;

FIG. 8 is a side elevation of the latch arm as used in the second embodiment; and

FIG. 9 is a schematic wiring diagram applying my principle of operation.

Referring now to FIG. 1 of the drawings, the clothes washing machine 10 there illustrated, is of the generally known spin-basket type. More particularly, the machine 10 comprises a substantially rectangular base 11 that is supported upon independently adjustable feet 12 arranged to engage the floor or other supporting surface. An enclosing housing or other casing 13 is removably carried by the base 11 and includes a conventional wraparound element including front, side and top walls. The sides of the top wall 15 are substantially flush with the side walls of housing 13 to form an upright substantially rectangular prism. At the rear of the top wall 15 is mounted a slightly vertically extending backsplasher 16 which serves as a control panel. The inner portion of this baoksplasher contains the control mechanisms and switches (shown only as rectangle 16.1 for initiating a cycle of the proper length and type. Purely by way of simplified example, there is shown a timer control knob 17 which is rotatable manually to set the desired length of the operative cycle.

A substantially centrally disposed stop opening 20 is provided in top wall 15 in order to render the interior of the housing 13 accessible. A conventional lid 21 is provided for the purposes of selectively closing the top opening 20'; the lid being hinged to top Wall 15 at its rear edge and movable thereabout from a closed position to an open position allowing access to the interior of the casing 13 for loading or unloading the machine.

A generally rectangular collection chamber or drain tub 23 is provided in the upper portion of housing 13. The bottom wall 26 of chamber 23 is welded or otherwise suitably sealed to the inner wall of the housing, and spaced above base 11 to define a machinery compartment 27 arranged in the lower portion of housing 13. Within this compartment there is provided a sup port structure 29 which serves as the foundation for the transmission and this support is mounted to base 11.

This support structure 29 comprises a horizontal base plate 30, vertical side walls 31 extending therefrom to join a top plate 31.1 in forming an open rectangular mounting space for the transmission mechanism 32. Secured to one side wall 31 is a curved channel member 35 towhich is bolted or affixed in any known manner the main drive motor 36. Motor 36 is positioned in inverted fashion with its output shaft 3-6.1 depending from the motor structure. Secured about the motor shaft is a coupling to a drain pump- (not shown) of any generally known type. The pump may preferedly have its impeller fastened to the motor shaft so that the pump may expel waste water on rotation of the motor. Further, the motor shaft has mounted to it a pulley 37 which carries a flexible V belt 3-8. This V belt is also laced about large diameter pulley 39 of the transmission mechanism 32, to impart a reduced speed driving eifect thereto. The transmission mechanism 32 is mounted in parallel relationship to the motor 36 and has extending upwardly above its topmost surface a central agitator shaft '45 which in its upward extent protrudes through the bearing retainer structure and into the collection chamber 23.

An upstanding spin basket 46 is centrally positioned within collection chamber 23 and is mounted for rotation about a substantially vertical axis. The spin basket is generally imperforate and has an open face adjacent the top access opening of the casing 13 to allow access to the basket interior. About the periphery of the basket adjacent the open face, there is secured an annular balance ring 46.1 of high density material providing a comparatively large moment of inertia for the basket. The spin basket 46 is provided with an upwardly and outwardly flared sidewall that terminates as mentioned below the access opening. Near its upper periphery basket 46 contains a horizontally aligned series of apertures or slots 47 for centrifugally ejecting water from the basket. At the center of the spin basket there is positioned a vertical agitator 48' which is mounted coaxially on the agitator shaft 45 and is oscillated thereby. Also mounted coaxially to the agitator shaft is a tubular spin shaft 49 whose upper end terminates a few inches above the spin basket lower surface. This spin shaft is used to impart rotative motion to the basket and to further this end, the spin shaft is firmly secured to the spin tub 46 at hub 49.1. The lower end of spin shaft 49 is mounted securely to the upper surface of transmission housing 32 so that the spin shaft and basket are corotative with the transmission housing 32. Exteriorly of the cylindrical body of the agitator 48 are positioned a plurality of radially extending agitator vanes 50. The agitator is further provided with an outwardly and down Wardly flared skirt '51 to which the vanes 50 are joined at their lower ends.

Turning now to the drive mechanism, there is provided as previously mentioned, a main drive motor 36. The motor comprises a reversible induction motor of the split-phase type which may be of the two-speed type, but for simplicity will be described herein as a singlespeed motor. The motor, a typical appliance motor, has a rating of about /3 horse power and an operating speed at full load of about 1,725 rpm. The motor, ingenerally known fashion, may be energized through selectable circuitry for rotation in the clockwise or counterclockwise direction to effectuate the necessary agitate and spin operations.

In FIGS. 2, 3 and 4 there is shown a first embodiment of a brake mechanism employing my invention. This brake mechanism includes a rotational brake housing 52 which confines a brake hand, later described. The housing structure is mounted on the transmission casing 32 in the area above the upper exposed surface 54 of the casing. The casing includes a cylindrical vertical extension 55 protrusive above the exposed surface. This extension in turn is secured in any suitable fashion to the spin shaft 49 so that both structures rotate simultaneously. Within this extension 55 there is provided a shoulder 56 on which rests a metal bearing washer 57. This Washer serves as a mounting base for the rotational mechanism 52. The housing 52 comprises an irregular cylinder of metal such as steel with various indented areas forming cam surfaces therein. First, there is a low horizontal platform fined by the upstanding wall 62. As apparent from FIG. 2, wall 62 spirals inwardly in opposition to the direction of rotation of shaft 49 during the spin operation. The area above the platform and outwardly of wall 62 const1tutes an opening in the brake housing. From a point (a) FIG. 2, which defines the limits of platform 64, an inclined plane or ramp 66 spirals upwardly for an angular distance of 270 more or less, and terminates in a vertically and outwardly extending terminal wall 68. This terminal wall extends radially from intermediate wall 62 to the peripheral wall 69 of the structure 52, By this construction, the terminal wall 68 is angularly and axially spaced from the platform 64 through the medium of the inclined plane 66 so that the approach to wall '68 from the plane of platform 64 is along the inelined ramp 66. Fitted into the cylindrical brake housing is a metal brake band 70* which fits tightly against the inner wall 71 of the housing. This brake band includes a tang 72 extending radially from the band proper, and positioned within a suitable notched area 73 within the wall structure 74 of the brake housing. Also within the notched area 73, there is positioned adjacent the tang 72 a suitable rubber cushion 75. Cushion 75, by virtue of its position, will absorb a large portion of any shocks transmitted to either of these members. Bonded to the inner surface of brake band 70 is a brake lining 76 which optimally is constructed of friction material suitable for use in braking high inertia devices. This brake lining is 64 of short radial depth as debonded to the interior of the band in such a manner that it fits tightly about the casing extension 55 so that the housing 5 2 will rotate with the casing and spin shaft 49 when the brake mechanism is maintained inactive, and the brake band will impose a considerable braking force when the brake mechanism is activated.

Adjacent the brake housing 52 there is mounted as part of the total brake mechanism structure, a latch member 80 which extends horizontally and tangentially toward the brake housing. A detent 82 extends radially toward the brake housing to enter into a latching relationship therewith, as presently explained. The latch member is pivotally mounted at the end most remote from detent 82. The pivotal mounting is accomplished by means of a pivot rod 34 depending from the stationary transmission support 311. About this rod there is mounted for free rotation a tubular bushing 86. At the bottom end of bushing 86 there is an annular flange 87 on which the latch member 85 rides. The flange rests freely on an expanded head of rod 84 and the flange and bushing are movable vertically on rod 84. A torsion spring 88 is coiled about the bushing and has one spring end 88.1 anchored to a stationary mounting member 38.2. The opposite or lower end of the torsion spring 88.3 is looped about the latch member to bias the latch member toward the brake housing. The spring also biases the latch member toward its flange 87. With this torsion spring and the mounting of bushing 86 on pivot rod 84, a limited amount of vertical travel of the bushing and its attendant latch member is permitted. At the detent end of the latch member there is connected a tension spring 90 which normally is inactive and allows the detent to respond to the urging of the torsion spring 88 and remain in the position shown in FTGS. 2. and 3. The remote end of the tension spring 91) is afiixed to the plunger 91 of a suit-. able electrically operated solenoid 92. Thus, when solenoid 92. is energized drawing plunger 91 into the solenoid proper, the tension spring 90 is activated and overcomes the normal urging of torsion spring 88 and as a result will draw detent 82 away from the brake housing.

To complete the structural description of the brake mechanism, as a further component there is provided a top bearing washer 94 which rests on the top of the casing extension '55 and serves to axially position the brake housing 52 with respect to the transmission casing while permitting one to rotate relative to the other. The brake housing wall 62 is provided with a vertically extending groove 96 which extends axially from the plane of platform 64 to the top of the brake housing. This groove extends radially inwardly from the platform wall substantially to the brake band. The groove is recessed to a width and depth sufiicient to receive detent 82 in a manner firmly locking the brake mechanism to the latch member.

The Washing machine shown herein is of the conventional type which through suitable control mechanisms governs the sequencing through a wash cycle which includes a wash fill, a wash agitation period and extraction period followed by one or more rinsing cycles. Each rinsing cycle will, of course, consist of a rinse till, a rinse agitate period and a rinse extract period.

To fully analyze the operation of the brake mechanism of the present invention, it is only necessary to view the operation during an agitate period and the subsequent extraction period, the other agitate and spin periods being identical for the purposes of this invention. 'No'w viewing specifically the functioning of this embodiment during a washing machine operation, it will be assumed that, after the preliminary steps the control mechanism has sequentially actuated the suitable components into an agitating cycle. During an agitate cycle the drive motor 36 is imparting a clockwise (as viewed in FIG. 2) rotative force to the gear mechanism and as a result agitator shaft 45 is oscillated within the spin tube 49. The clockwise rotative force on the gear mechanism imparts a tendency toward sympathetic spin and oscillation on the transmission casing. 011 machines which utilize no positive braking apparatus, the transmission casing tends to move with an action which can best be described as oscillation superimposed on rotation, a speed which may reach 13-15 rpm. This movement on such machines is transmitted through the spin shaft to the spin basket. The basket then describes this oscillatory rotation which ends to impede the normal wash action and may also cause damage to the laundry in the basket.

During the agitate cycle on the present machine as equipped with a positive brake mechanism, the function of the brake mechanism during the agitate cycle is to hold the spin basket substantially stationary while the centerpost agitator oscillates. What is considered substantially stationary is rotation on the order of 4 rpm. or less. In the agitate cycle, solenoid 92 remains deenergized and latch maintains its position under the normal urging of torsion spring 83-. Torsion spring 88, as previously mentioned, biases latch 80 toward the brake housing so that detent 8 2 is prepared for locking engagement therewith. If transmission casing 32 oscillates, and more particularly during the clockwise portion of the oscillatory movement, detent 82 will slidingly contact plat-form 64 and will slide into engagement with groove 86 (as shown in FIG. 2). With this engagement, the brake mechanism will be anchored to the latch and the engagement of the brake band with the extension 55 will resist a large proportion of the attempt at rotation or osci-llation.

As the control mechanism drives the machine elements into the extract or spin operation by suitable circuitry (not shown), solenoid 92 will be energized and will draw its plunger in the direction away from the brake housing. This plunger movement will draw latch member 80 away from the brake mechanism. This plunger movement will overcome the contrary urging of torsion spring '88- and will draw the latching detent '82 out of groove 96. The detent will thereby be held in a position out of engagement with the brake mechanism as long as solenoid 92 remains energized. In the spin cycle the drive motor 36 will rotate the gear transmission casing through the belt and pulley system previously described and as a result casing 32 will rotate in the counterclockwise direction as viewed in FIG. 2. The latch mechanism having been withdrawn from engagement with the brake mechanism, no impediments to rotation are encountered in the path of travel of the brake mechanism. Gear casing 32 rotates and in turn rotates spin shaft 49 and spin basket 46 to extract liquid from the tub at a high rate of speed.

This unimpeded rotation continues until one of a number of conditions occurs. One of these conditions may be the conclusion of the time allotted within the sequence for the extraction operation. Several makes of washing machines in present manufacture have a main power switch such as 98, FIG. 1, which is held closed by the weight of the machine lid 21. In such machines, a second condition which may occur is that of the machine lid having been opened. An emergency condition may include excess gyra-tion of the basket actuating a shut-off mechanism. This arrangement, also, is well known in the art. Following any of these occurrences, the spin basket rotation should be terminated rapidly. To effect this stoppage of rotation, suitable generally known electrical switches are actuated opening the energizing circuit to solenoid 92.

The circuitry shown in FIG. 9 is schematic, for all the necessary components are old and well known. Timer-driver cam 10% is of the three-level type, in which the lowest level closes cam follower 101 against contact 102 to energize the reversible motor 36 in its spin direction; the upper cam level closes the follower against contact 103 to energize the motor in its agitate direction; and the intermediate level establishes an open circuit condition. It will be apparent that when the motor is in spin condition, an open lid switch 98 will deenergize the motor and the solenoid 92. The lid switch has no such control when the motor is in agitate condition. When the cam 100 runs out the spin cycle and restores follower 101 to its intermediate level, both the motor and solenoid are deenergized. When solenoid 92 is deenergized, latch 80 is under the control of torsion spring 83, which impels latch 80 in the direction toward the brake mechanism, detent 82 then assuming a position adjacent brake housing 62. The brake housing, it must be remembered, is rotating in a counterclockwise direction during this high speed extraction rotation. Further, it should be remembered that torsion spring 88 tends to maintain latch 80 and detent 82 in a horizontal plane substantially as shown in FIG. 3. In this horizontal plane detent 82 is positioned axially just above the level of platform 64. As detent 82 approaches the brake housing, either of two conditions may occur during a rotation of the brake housing. In a first of these conditions, the area of upstanding wall 69 may be found within the area to which the latch detent is impelled. If this condition occurs, the detent will strike the upstanding wall at its periphery, the detent will slightly rebound from the wall and rotation will continue. As the brake housing continues through the same revolution, the inertial effect of the latch mechanism having been deflected outwardly by the rapidly rotating outer wall 69 will tend to maintain the detent at the same radial distance from the drive shaft. This inertial effect will be continued for a finite time period after the outer wall '69 has completely passed the detent. This period is sufficient to cause the brake housing to have rotated groove 96 past the detent 82, alleviating the possibility of this engagement. As the brake mechanism continues its rotation, detent 82 will be biased radially inwardly toward the center of the rotating assembly and will encounter the open recessed area above platform 64. In the area above the low platform 64, the detent will find little resistance to inward movement and will continue to move inwardly until it strikes the inner wall 62 of the brake housing. The rotation of the brake mechanism continues and detent 82 will be guided upwardly along the rotating inclined plane 66. As the detent rides along this ramp surface, it is allowed further inward movement by the spiral wall of housing 62. At the top of this inclined ramp, detent 82 will finally be guided into engagement with the radially extending wall 68. T he engage ment of the terminating wall and the latch detent immediately arrests rotation of the brake housing and braking force is transmitted from radial wall 68 through cushion 75 to tang 72 to band 70' and ultimately through the brake lining 76 to the transmission casing 32. It will be evident that there is a slight relaxation of the brake band 70. This renders the braking action less abrupt, and reduces the shock load which would otherwise be imposed on the casing 32. Nevertheless, the frictional engagement of brake lining 76 with extension 55 brings the casing 32 and its thereon mounted spin shaft to a stop.

Now turning back to the instant of engagement between the latch and the brake mechanism, it should be noted that the torsion spring 88 nominally maintains detent 82 in a plane just above horizontal platform 64. When the contact between the detent and the wall 69 occurs in the area from groove 96 to radial line (a) approximately 90 away, the detent will enter the platform indentation, will contact wall 62 and ride up the ramp. The slide action of bushing 86 on the pivot rod 84 follows the guided movement of the detent under the bias action of torsion spring 88 by sliding up pivot rod 84 and moving the plane of the latch upin like amount until terminal wall 68 is encountered' to initiate the braking action.

If however, the preliminary contact between the latch and the housing occurs in the angular area from line (a) to the terminal wall '68, which in the example shown in FIG. 2 encompasses about 225, the detent 82 will strike the periphery 69 of the housing, which in this area is higher than the plane of operation of the latch 80. The detent will thus be restrained outwardly of the housing until platform 64 has rotated to a position adjacent the latch detent for contact therewith. As mentioned previously, within the area of platform 64 detent 82 will enter the brake housing to contact wall 62. Slide motion of the latch up the ramp will follow leading to the brake action engagement. By this construction, it is ensured that there is a contact of over 180 of revolution between the brake mechanism and latch before the braking engage ment between detent 82 and radial terminating wall 68 is reached to initiate the braking action.

A second embodiment of the brake mechanism is shown in FIGS. 58 inclusive. The brake mechanism is quite similar to the prior embodiment generally and is mounted about gear casing extension 55a above and integral to casing 32a. Casing 32, extension 55a, and spin tube 49a are all firmly afiixed to one another for rotation, as in the earlier described embodiment. On the shoulder of the casing above exposed surface 54a of casing 32a, there is mounted the brake housing which may be described as a cylinder with a sloping upper wall surface or ramp surface 112, the development of which is shown in FIG. 7. Ramp 112 may be considered as a cam surface which is radially level and extends from a low plane at line 114 to a high line at 116. In one direction the ramp surface extends from line 114 to line 116 for a distance of 270 considered angularly, and in the other direction extends 90 from low to high. At the high position reached by line 116, a radially extending tang 120 protrudes from an annular metal brake band 122 into a sized notch in the inner edge of the upper surface at line 116. This tang extends radially only partially to the outer periphery 124 of the brake housing 110. The brake band is of generally known incomplete tubular form as with the first described embodiment. Bonded to the inside of the brake band is a brake lining 126 of suitable friction fabric which as in the previous embodiment tightly encircles extension 5511 of the casing 32. -A positioning annular washer 127 and suitable snap ring 128 of extended vertical height may be used as a spacer and to position the brake mechanism relative to the extension 55a and stationary support 31a. This snap ring extends vertically from the top surface of the brake housing substantially to the stationary adjacent support 31a as can be seen best in FIG. 6. As in the prior embodiment, the brake housing, brake band and lining rotate with the gear casing and spin tube on spin rotation in the counterclockwise direction, when no impediments to rotation are encountered.

To provide the latching impediment to rotation when required, a latch arm 130 is pivotally secured to the adjacent support wall 31a at a pivot rod 132. On either vertical side of the connection of latch arm 139 to the pivot rod, there is provided a rubber bushing, namely, 134 and 136, which combine to allow the latch member a limited amount of tilting movement in the vertical direction in addition to the pivotal motion about rod 132. Latch member 130 (seen in detail in FIG. 8) includes a stepped portion which horizontally spaces the mounting end 140 from the latching end 142. Latching end 142 includes an inwardly concave section 144 which substantially matches with the circularity of the outer periphery of brake drum 122. Further along this inner latch surface, in the direction toward its pivot axis, the latch end 142 is grooved at 146 with a recess large enough to seat tang 120. Recess 146 and concave section 144 are in the same horizontal plane within latch end 142. With latch arm 130 held horizontally, the plane of end 142 is at a lower level than that of the pivot end 140. At this lower end, the latch arm 130 is biased toward the brake mechanism by a tension spring 150 anchored to any suitable stationary member such as an extension (not shown) of support 31a. Acting in the direction opposed to spring 158, is a link 152 which is secured to the latch arm adjacent groove 146 and extends from the opposite side thereof. This link is secured to the plunger 154 of solenoid 156 so that energization of the plunger withdraws link 152 and latch 130 from possible contact with the brake mechanism. Solenoid 156 may physically be secured in any known fashion to the stationary structure 31a.

The operation of this embodiment is quite similar to the mode of operation of the prior embodiment. During the agitation portion of this cycle, transmission casing 320: is oscillated sympathetically with but little power by oscillation of the center shaft 45a. Solenoid 156 remains deenergized allowing spring 150 to advance the latch 130 toward the brake mechanism. During the oscillation of the casing 320, concave section 144 will at some time reach low area 114 and be drawn against the brake drum. With continuing oscillation, concave section 144 will ride up the slope 1-12, presumably up the comparatively short 90 angular slope due to the prevailing clockwise rotation of the input to the transmission and when the latch arm reaches high line 116 on the cam surface, tang 120 will engage with recess 146 and latch the brake mechanism to arm 130. In actuality, this action as described will occur infrequently as the latch once having locked to the brake mechanism at the conclusion of the last spin will maintain this engagement until the start of the next spin operation.

With the start of spin, solenoid 156 is actuated, drawing its plunger 154 inwardly and pulling link 152 to withdraw the latch from the brake to allow unimpeded counterclockwise rotation of the spin tube, gear casing and casing extension. Solenoid 156 is held energized throughout the spin cycle and is deenergized by a signal indicating the end of spin period, unbalance, power loss, or by the opening of the lid control switch circuit, any condition of which signifies that the basket rotation is to be halted. With any one of these occurrences, solenoid 156 is deenergized as the basket, transmission casing and spin tube continue to rotate at high speed. Engaging end 142 of the latch is released from the restraint imposed by the solenoid and is biased by spring 150 toward the brake housing in the plane adjacent the low spot 114 on the cam surface. At all radial positions on the housing other than within a small area on either side of low area 114, concave section 144- will strike the housing outer wall 124 and the rotation of the housing will continue. When the low section 114 in the continuing rotation reaches an angular position adjacent the latch end 142, concave surface 1-44 is allowed to penetrate the housing area and strikes brake band 122. After this initial contact has been made, rotation of the spin tube and brake housing continues as latch end 14-2 rides up the inclined plane 112. As the rotation continues, tang 121 contacts the inset portion 160 of the latch 130. This contact of tang and inset leads the tang into latching engagement with groove 146. The latching engagement locks the brake band 122 to the stationary structure through the latch. This has the effect previously noted: it slightly relaxes the brake lining 126 on the casing extension 55a to brake the casing Without imposing an excessive shock load. Nevertheless, because of the frictional engagement of the brake band lining 126* with extension 55a, the spin tube and the basket come to a stop within a matter of seconds. This latch brake once engaged remains engaged until such time as solenoid 156' is energized, during spin only.

While there has been described what is at present thought to be the preferred embodiments of the invention, it will be understood that various modifications may be made therein, and it is the intention to cover all such modifications as fall within the true scope of the invention.

What is claimed is:

1. A brake mechanism for a structure which includes a stationary support and a rotor rotatable adjacent said support, comprising:

a cylindrical brake housing and band circumposed about said rotor,

a latching member pivotally secured to said support and biased toward said rotor in a plane perpendicular to the rotational axis of said rotor whereby said brake housing arrests further pivotal motion of said member and allows rotation of said rotor,

a recess of limited extent in said brake housing adjacent the pivotal plane of said member for receiving said member on pivoting thereof,

a cam surface spiralling about said housing from said recess for conducting said member therealong on rotation of said rotor following receipt of said member,

a contact shoulder spaced angularly and axially about said rotor from said recess,

said contact shoulder extending radially from said brake housing at the end of said cam surface for stopping the conducted motion of said member and engaging said member, means on said brake band responsive to said engagement for actuating said brake band and for latching to said member for stopping rotation of said rotor.

2. A brake mechanism for a machine which includes a stationary support structure and a rotor mounted on said structure for rotation relative thereto, comprising:

a brake band disposed about said rotor in frictional engagement therewith,

a housing about said brake band and engaging there- 'with for conjoint rotation of said housing, brake band, and rotor, said housing having a ramp spiralling upwardly thereabout,

a latch member pivotally secured to said support struc ture,

means for biasing said latch member for rotation toward said housing in a plane normal thereto and immediately above the low point of said spiral ramp whereby said latch member may enter above said ramp only at the low point thereof,

wall means extending radially of said ramp at the high point thereof for engagement by said latch member to interrupt rotation of said housing and brake band and thereby effect deceleration of said rotor,

and means for disengaging said latch member from said housing.

3. In a washing machine having a stationary frame structure, a spin basket, and a motor for rotating said basket, the combination comprising:

a basket-rotating shaft adapted to be rotated by said motor,

a cylindrical brake housing disposed about said shaft for rotation relative thereto,

a brake band fixed within said housing extending about said shaft in frictional engagement therewith, whereby said housing and said shaft may rotate concurrently,

a latch member having a nose portion extending toward said housing,

means providing a ramp about the exterior of said housing, said ramp having a low point immediately below the plane of said latch member and spiralling upwardly about said housing to terminate in a radially extending wall structure,

means for mounting said latch member for displacement in a first plane normal to the axis of rotation of said housing and in a second plane parallel thereto,

and means for effecting displacement of said latch member in said first-named plane to engage with said housing in surface contact with said ramp, whereby rotation of said housing relative to said latch member ultimately effects engagement of said housing wall structure with said latch member and consequent interruption of rotation of said housing and deceleration of said shaft.

4. In a washing machine having a stationary frame, a spin basket, and a motor for rotating said basket, the combination comprising:

a basket-rotating shaft adapted to be rotated by said motor,

- a brake supporting structure disposed about said shaft for rotation relative thereto,

. a brake bandfixed within said supporting structure extending about said shaft in frictional engagement therewith, whereby said brake band and said shaft may rotate concurrently,

a latch member having an end portion extending toward said supporting structure,

means providing a ramp about the exterior of said supporting structure, said ramp having a low point immediately below the plane of said latch member and spiralling upwardly about said supporting structure,

means at the top of said ramp engageable by said latch member end portion to interrupt rotation of said brake band,

means for mounting said latch member for displacement in a plane normal to the, axis of rotation of said housing, said mounting means providing for movement of said latch member end portion axially of said supporting structure,

means for efiecting withdrawal of said latch member relative to said housing,

and means ttor effecting displacement of said latch member in its said plane to engage the latch mem ber end portion with said housing in surface contact with said ramp, whereby rotation of said housing relative to said latch member ultimately bring said end portion into operative association with said brake hand to interrupt rotation thereof and effect deceleration of said shaft.

5. In a washing machine having a stationary frame, a spin basket, and a motor for rotating said basket, the combination comprising:

a basket-rotating shaft adapted to be rotated by said motor,

a brake supporting structure disposed about said shaft for rotation relative thereto,

a brake band :carried by said structure and encircling said shaft in frictional engagement therewith, whereby said structure and said shaft may rotate concurrently,

a latch member having an end portion extending toward said structure,

.means providing a ramp on said structure, said ramp having a low point immediately below the .plane of said latch member and spiral-ling upwardly about said structure, said brake band having a radially extending end wall defining the uppermost end of said ramp, 7

means for mounting said latch member on said frame for displacement in a plane normal to the axis of and means for eifecting displacement of said latch member in its said plane to engage the latch end portion with said housing in surface contact with said ramp, whereby rotation of said housing relative to said latch member ultimately effects engagement of said brake band end wall with said latch memher and consequent interruption of rotation of said brake band and deceleration of said shaft.

. 6. in a washing machine having a stationary frame, a spin basket, and a motor operable in either forward or reverse direction, the combination comprising:

a basket-rotating sha ft adapted to be rotated by said motor,

a latch lever having a nose portion extending toward said housing,

means providing a ramp on said housing, said ramp having a low point immediately below the plane of said latch lever and spiralling upwardly about said housing to terminate in a radially extending wall structure,

wall means providing a detent pocket in said housing on the level of the low point of said ramp,

means for mounting said latch lever for displacement of the nose portion thereof in a first plane normal .to the axis of rotation of said housing and in a second plane substantially axially of said housing,

a solenoid mechanically associated with said latch lever,

electric circuit means for energizing said solenoid to withdraw said lever from said housing upon concurrently energizing said motor =for operation in one, only, of said motor operating directions,

and spring means efiective upon concurrent deenergization of said motor and solenoid to move said lever to bring the nose thereof for engagement with said detent pocket or into overlying relation with said ramp according to the angular displacement of said pocket relative to said nose at the time of such lever movement, whereby maximum delay in interruption of rotation of said housing is represented by the time required for said nose to traverse said ramp and engage with the radial wall means defining the end thereof.

References Cited in the file of this patent UNITED STATES PATENTS 279,033 Smith June 5, 1883 962,141 Hartmann June 21, 1910 1,788,110 Junghans Jan. 6, 1931 2,807,951 Gerhardt et al. Oct. 1, 1957 2,946,409 Jennings July 26, 1960

Claims

1. A BRAKE MECHANISM FOR A STRUCTURE WHICH INCLUDES A STATIONARY SUPPORT AND A ROTOR ROTATABLE ADJACENT SAID SUPPORT, COMPRISING: A CYLINDRICAL BRAKE HOUSING AND BAND CIRCUMPOSED ABOUT SAID ROTOR, A LATCHING MEMBER PIVOTALLY SECURED TO SAID SUPPORT AND BIASED TOWARD SAID ROTOR IN PLANE PERPENDICULAR TO THE ROTATIONAL AXIS OF SAID ROTOR WHEREBY SAID BRAKE HOUSING ARRESTS FURTHER PIVOTAL MOTION OF SAID MEMBER AND ALLOWS ROTATION OF SAID ROTOR, A RECESS OF LIMITED EXTENT IN SAID BRAKE HOUSING ADJACENT THE PIVOTAL PLANE OF SAID MEMBER FOR RECEIVING SAID MEMBER ON PIVOTING THEREOF, A CAM SURFACE SPIRALLING ABOUT SAID HOUSING FROM SAID RECESS FOR CONDUCTING SAID MEMBER THEREALONG ON ROTATION OF SAID ROTOR FOLLOWING RECEIPT OF SAID MEMBER, A CONTACT SHOULDER SPACED ANGULARLY AND AXIALLY ABOUT SAID ROTOR FROM SAID RECESS, SAID CONTACT SHOULDER EXTENDING RADIALLY FROM SAID BRAKE HOUSING AT THE END OF SAID CAM SURFACE FOR STOPPING THE CONDUCTED MOTION OF SAID MEMBER AND ENGAGING SAID MEMBER, MEANS ON SAID BRAKE BAND RESPONSIVE TO SAID ENGAGEMENT FOR ACTUATING SAID BRAKE BAND AND FOR LATCHING TO SAID MEMBER FOR STOPPING ROTATION OF SAID ROTOR.