US2681071A - Fluid pressure regulator responsive to angular velocity and acceleration - Google Patents

Description

June 1954 s. l. GABRIELSON ETAL 2,681,071

FLUID PRESSURE REGULATOR RESPONSIVE TO ANGULAR VELOCITY AND ACCELERATION Filed Dec. 24, 1948 Fig.1.

Ihvntors: Samuel LGabridson,

Jacqb W. Mc b lanfy,

Patented June 15, 1954 UNITED STATES PATENT OFFICE FLUID PRESSURE REGULATOR RESPONSIVE TO ANGULAR VELOCITY AND ACCELERA- TION Application December 24, 1948, Serial No. 67,212

. 3 Claims.

This invention relates to an improved clutch control for washing machines of the type in which the clothe are washed and spin-dried in the same basket, and particularly to a hydraulic fluid regulator for a clutch control.

A popular type of such washing machines includes a tub within which a basket is mounted for rotation. An agitator or other mechanical washing device in the tub imparts motion to the clothes within the washing liquid. By means of a motor and suitable drive gearing, the agitator is oscillated during washing and rinsing periods, and after the final rinse and drain, the basket is rapidly spun in order to extract the water from the clothes by centrifugal action. Because the weight of clothes and the water contained therein may be substantial the motor is subjected to a relatively heavy load at the commencement of the basket spinning phase of operation.

Torque responsive means have heretofore been provided for disengaging the drive clutch to prevent overloading the motor. However, it has been found that the motor may stall before the torque responsive means becomes effective and the power line to the motor may thereupon become overloaded beyond the capacity of the line fuses. Another objection to the torque responsive clutch is that low line voltage may cause the motor to stall under the initial load. This condition arises most frequently in residential installations in which a refrigerator, iron, or similar appliances may be on the washing machine circuit.

The present invention provide a clutch control which is responsive to motor speed rather than generated torque, including an improved centrifugally operated control element for the clutch. This element is suitably mounted on a rotatable clutch plate to be responsive to tangential inertia forces, as well as centrifugal forces, and in such a manner that tangential inertia forces during acceleration and deceleration have an independent controlling effect tending to dampen the reaction of the element to changes in the rotational speed of the clutch plate. Consequently, the tendency of the control element to hunt or cycle is minimized. This control element causes the basket clutch to automatically disengage when the motor speed drops to a predetermined point, preferably suitably above the motor stall point, so that the motor will not remain under load until it stalls. For example, if the basket load is such that motor speed falls toward the danger level, the control will operate to disengage the clutch-at least to the extent of permitting slip-before the motor is overloaded. In extreme cases the clutch members may rapidly engage and disengage several times before a permanent clutch closure is effected. Reasonable drops in line voltage do not adversely affect the operation of the device inasmuch as the clutch engagement is dependent upon motor speed rather than on relative torque requirements.

It is therefore an object of the invention to provide an improved centrifugally operated speed responsive clutch control for washing machines of the single basket, spin-dry type.

It is a more specific object of the invention to provide a speed responsive control for a washing machine in which the reaction of the control element to speed changes is damped by its tangential inertia.

It is still a further object of the invention to provide a clutch control which is simple and inexpensive to manufacture and will operate over long periods of time without failure.

These and other features and advantages of the invention will be apparent in the following detailed description of a typical embodiment, with reference to the accompanying drawing, in which: Fig. 1 is a vertical section taken through the motor and clutch assembly of a conventional washing machine, and showing the drive gear casing only fragmentarily; Fig. 2 is a plan section taken on the lines 22 of Fig. 1, showing the control elements at rest; and Fig. 3 illustrates the control elements in clutch-engaged position.

Fig. 1 shows so much of a washing machine motor and driving assembly as is necessary for an understanding of the invention. A housing which is suitably mounted in the washing machine frame (not shown), has an upper portion I0 and a lower portion l I, suitably secured at an intermediate web structure l2. The housing portion In contains the gear casing I l within which is a suitable gear train (a portion of which is shown at I5) for oscillating an agitator or other washing device disposed Within a conventional basket having an axis connected to the gear casing 14 so that said basket will be rotated as the entire gear casing 14 is rotated. This agitator, basket, and'gear casing arrangement is well known in the art, and. has not been detailed herein.

The motor l5 has a stator Il' fixed Within the casing part II. Said stator has conventional starting and running windings collectively identified by the reference IS. The stator core may have one or more oil drainage passages. 20 extending therethrough and. may also provide for an oil tube 2| for pressure lubrication of the gear train I5 and the bearing member 22 of gear casing M. The motor rotor 23 has a tubular shaft 24 which seats within a bearing 25 provided in a part of the supporting structure 26 fixed to the bottom wall of the casing H as shown. An eccentric chamber 21 for a conventional vane pump is formed in the structure 26 beneath shaft 24. A tubular hub 29 integral with or fixed to the end of shaft 24 for rotation therewith drivingly supports the pump vanes 28. An axial aperture 3!; in shaft 24 registers with the bore of hub 29 and an opening 3| in a pump chamber cover 32 to afiord communication with an oil pressure chamber 33 provided by a dished plate 34. A passage 35 through the closure plate 32 affords a second path of communication betwen the pump chamber and the space 33. An outlet passage 36 serves the lubrication duct 2|. The plate 34 has an aperture 37 which serves as a seat for a plunger valve 38 which is activated by a solenoid 39. A cup forms an oil sump into which the pump inlet tube 4| reaches. 7

As is known in the art, the operation of a washing machine of the single basket wash and dry type includes periods of oscillation of an agitator or similar washing mechanism, and periods in which the basket is spun at high speed. During agitation, the basket is held stationary by a suitable friction brake or equivalent; under spin condition, the agitator is released for free movement and will rotate with the basket. Two clutches are provided: one to drive the agitator, and one to couple the gear casing to the motor to be rotated thereby, the gear casing being drivingly connected to the spin basket. The agitator clutch is normally engaged; the weight of the agitator shaft and its accessories is sufficient to hold it in engagement and to return it to engaged position. The gear casing clutch is normally disengaged; its driven clutch member is resiliently held in frictional engagement with a fixed brake shoe.

Oil pressure generated by the pump vanes 28 is used to disengage the agitator clutch and engage the spin basket clutch. As will be presently explained the agitator clutch disengages shortly before the basket clutch is engaged.

An agitator drive shaft 42 to which the main drive pinion 42a is fixed, is rotatably journaled in bearing sleeves 43 within the motor shaft 24. Said sleeves are slotted to provide one or more oil fiow passages 44. The agitator clutch is advantageously of cone clutch type, the driving member 45 of which is fixed to the rotor 23. Cooperating with said clutch member is a complementary member 46 suitably fastened to the shaft 42. When said clutch members are in engagement shaft 42 will be power driven, to drive the agitator mechanism during the washing cycle.

The spin clutch drive plate 48 is supported on shaft 42 by a sleeve 41 freely rotatable and axially moveable on shaft 42. The complementary clutch member 5% is secured to the gear casing [4 by means of a flanged cap 5i having any desired plurality of slots 52 through which fingers 53 of clutch member extend. By means of a spring 54, clutch member 50 is held in resilient contact with a brake shoe 55 secured to housing member l2. During the agitate cycle of operation of the machine, the gear casing i4 is held against rotation by the brake shoe 55. The driving clutch member 48 is secured to motor rotor 23 by means including a cap 56 directly secured to the rotor as shown, and a flexible bellows 5! having end plates secured to clutch plate 48 and cap 55, in fluid tight relationship therewith. The bellows operates as an axially extensible coupling, and is preferably of metal adequate for transmitting substantial torque loads without failure. A spring 58 interposed between cap 56 and a shoe 59 carried by sleeve 4'! serves to urge said sleeve and thereon secured clutch member 48 downwardly to maintain the clutch parts 48 and 50 in normally disengaged condition.

As presently described, the bellows 5'! is normally full of oil and it is by increasing the oil pressure within the bellows that the clutch parts 48 and 50 are engaged and the gear case l4 connected to the rotor for rotation of the basket. The bellows is provided with a centrifugally responsive valve assembly which will open to relieve the bellows pressure when the motor speed drops toward the stall point. A satisfactory valve assembly comprises a valve body 56 extending through the central web of clutch 48 into the bellows and having an inlet port 6! extending through its wall. Advantageously, the valve body is fixed to a mounting plate 62 which is riveted or otherwise suitably secured to the clutch plate web. An arm 63 extending from the mounting 62 provides a spring anchorage. The valve plug 84 is rotatably housed within the body 60 and has a passage 65 which, under certain conditions, will register with the body opening 6| to permit oil to flow out from the bellows into the space between the clutch plates 48 and 5E! whence it will return to the sump 4|]. The valve plug is actuated by a relatively heavy arm 66 secured thereto, said arm extending about the bearing sleeve 4'! as shown in Fig. 2. Preferably, the arm is self-weighted, although weights may be applied thereto. The bearing sleeve provides a limiting stop. A spring 6? anchored in the arm 63 and a suitable eye provided in the lever 65 tends to return the lever 6t and its associated valve plug to the position in which the body port BI and the plug passage 55 are in registry to permit a free outflow of oil from the bellows. The rotor 23 rotates counterclockwise and as a result, the weighted lever 65 is thrown outwardly by centrifugal force so as to wholly or partially misalign the body port 5! and plug passage 65 and either bleed oil from the bellows or prevent the escape of oil therefrom, according to the speed of rotation of the clutch plate 48. Suit ably before the stalling speed of the motor has been reached, the valve will be in full open position. The inertia of the lever 65 is such that it will resist return rotation for a moment, despite the urging of the spring 67, while the velocity of the clutch plate 48 is decreasing. The deceleration in the rotational velocity of the lever 65, caused by the deceleration of the clutch plate 48, creates a tangential inertia force on the lever 66 urging it to fly outwardly to the position of Fig. 3. This tangential inertia force resists the return pull of the spring 61 independently of the centrifugal force on the lever 56, which centrifugal force may have decreased because of the speed reduction to a point below that necessary to balance the spring force. Consequently, during deceleration the lever 66 is urged outwardly in opposition to its spring force, thus damping the reaction to the decreased centrifugal force. In the same manner a rapid acceleration of the clutch plate 48 causes a tangential inertia force on the lever 66 which in this instance is additive to the spring force in opposing aesnovr 5.. theincreased centrifugal force. and thus again dampens-the reaction of the lever to the velocity change. Since the tangential: inertia forces are proportional to the angular acceleration of the clutch plate 48, they have no eifect during periods of constant rotational velocity of the clutch plate and have the greatest effect during rapid changes in the rotational velocity. As a consequence the movement of the lever 66 in response to velocity changes of the clutch plate 48 lags the change because of the effect of the tangential inertia forces during these periods of acceleration and deceleration. In other words, the operation of. the valve plug 65 lags behind the increase or decrease of rotational speed of clutch plate 48. The operation reduces hunting and tendsto smoothout the operation of the valve and the thereby controlled bellows.

It will be notedthat the entire valve structure, including the mounting plate .62 and the lever 66, is assembled as a unit. Its application to the clutch plate is greatly facilitated.

The machine is shown in Fig. 1 in the agitating phase of operation. The solenoid 39 is de-energized and its valve plug 38 has dropped away from the valve port 37. Oil from pump 29 circulates in part through the passage 36 and the lubrication duct 2| and in part through the orifices 35, 3! and and the bore of the valve hub upwardly along the shaft 42 into the space it between the clutch plates 55 and 4B, and then through orifices H and 12 into the bellows 51. The motor operates at high speed during the agitating cycle and the bleed valve from the bellows will be closed. However, although the bellows may therefore be substantially full of oil it will not be at a high enough pressure to raise the clutch plate 48 for the reason that a major part of the oil output from pump 29 passes through the ports 3| and 31 for return to the sump. This being the path of least resistance, it effectively prevents the generation of oil pressure sufficient either to lift clutch plate 46 out of engagement with or to raise the clutch plate 48 into engagement with plate 50. Therefore, the shaft 42 is being driven by the motor and the gear casing :4 is at rest on the brake drum 55.

When the operation of the machine is to change over from agitating to spin, a suitable control (not shown) energizes the solenoid 39 to drive the responsive plunger 35 into seated position on the port 31. The recirculation of oil from and to the sump 4B is therefore halted and oil will flow under substantial pressure through the ports 35 and 3| along the shaft 42 into the clutch space 10. The size of the orifices 'H is such that they permit the generation of oil pressure within the space 10 to lift the clutch plate 46 (it being understood that this also entails a vertical movement of the shaft 42) and the shaft is thereby disengaged from the motor. The bellows bleed valve is completely closed during the agitating cycle due to motor operation at rated speed; therefore, the oil being confined to the bellows 51, said bellows will immediately rise to the level necessary to lift clutch plate 48 into engagement with plate 50. It will be noted that oil pressure is maintained by flow into the bellows through ports H and the annular space between the then separated clutch plates 45, 46. After a very short slip interval the clutch plate 48 will lift the plate 50 free of the brake drum and the gear casing l4 and its associated spin basket will begin to rotate. If the load of the spin basket causes a drop in motor speed the bleed valve will open in proportion to the drop and the bellows'will'collapse under the effect-of spring 58 until the clutch member 50 is lightly in contact with the brake 55. At this point slippage between plates 48 and 50 will permit the motor to speed up until the creation of pressure within the bellows again lifts the clutch plate 50. It should be understood that under all normalconditions of operation the rotor basket, once it has started to spin will continue to spin, eventhough slowly, for a suflicient interval to permit reclosure of the valve andreactuation of the bellows. on

engagement of the respective clutch platesand 50 will increase the rotational speed of the basket. and under rated basket loads operation will quick- 1y reach the point of 'continuedmotor drive. The

bellows operation is rapid and the relatively light engagement of the clutch plate 50 on =the-' brake 55 during bellows retraction and expansion is therefore of very short duration.

Pressure relief in bellows 51, even though it permits the bellows to withdraw clutch plate 48, does not afiect the operational status of the agitator clutch. Even at stalling speed of the motor, the oil pressure generated by the vane pump maintains adequate fluid pressure in the system, and the flow through ports "H and between the separated clutch members 45 and 46 is relatively so small that the agitator clutch will not re-engage. It is only when the solenoid is de-energized to reestablish the fluid circuit from and to the sump 48 that pressure will drop sufliciently to permit re-engagement of the agitator clutch. Such a pressure drop will permit spring 58 to drive sleeve 4'! and therewith associated plate 48 into disengaged position notwithstanding the operating position of the bleed valve port 65.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. In a rotatable pressure regulator for a fluid system, in combination, a rotatable support plate, a sleeve carried by said plate and spaced from the axis of rotation thereof, said sleeve being provided with a port in a side wall thereof, a valve plug rotatably disposed within said sleeve and provided with a passageway opening to the exterior of said sleeve at one end and normally communicating with said sleeve port at its other end, and a weighted arm carried by said plug and resiliently biased to a position contiguous to the axis of rotation and trailing said valve plug relative to the direction of rotation of said support plate, said arm being movable in response to centrifugal force to rotate said plug to restrict said sleeve port, the tangential inertia of said arm damping said valve operation by initially opposing the response of said arm to any change in the centrifugal force acting thereon.

2. In a rotatable fluid pressure control system including a rotatable disk, a pressure control valve comprising, a sleeve carried by said disk with the sleeve axis parallel to and displaced from the rotational axis, said sleeve having a port opening in the wall thereof, a valve plug rotatably disposed within said sleeve and provided with a passageway having one end adapted to be aligned with said sleeve port and its other end opening to a point exterior of said sleeve and plug, a weighted arm fixed at one end to said plug, and means biasing said arm toward the axis of rotation and trailing said valve plu relative to the direction of rotation of said disk, said arm being movable in response to centrifugal force away from said rotational axis to rotate said plug and thereby restrict said sleeve port, the tangential inertia of said arm damping said valve operation by initially opposing the response of said arm to any change in the centrifugal force acting thereon.

3. In a rotatable pressure regulator for a fluid system, in combination, a rotatable support plate, a sleeve carried by said plate with the sleeve axis displaced from and parallel to the rotational axis, said sleeve having a port opening through the side wall thereof, a valve plug rotatably disposed within said sleeve and provided with a passageway open to a point exterior of said sleeve at one end and normally aligned with said sleeve port at its other end, a weighted arm carried by said plug and trailing said valve plug relative to the direction of rotation of said plate, and spring means biasing said arm toward the axis of rotation, said arm being movable by centrifugal 8. force away from retracted position, thereby to rotate said plug and restrict said sleeve port, a. force component on said arm resulting from angular acceleration being opposed to said centrifugal force, thereby to damp said valve operation by initially opposing the response of said arm to any change in angular velocity.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,780,293 Christie et al Nov. 4, 1930 2,163,203 Kegresse June 20, 1939 2,275,204 Smirl Mar. 3, 1942 2,325,814 Tyler Aug. 3, 1943 2,328,091 Nutt et a1. Aug. 31, 1943 2,427,779 Haines Sept. 23, 1947 2,462,657 McNairy Feb. 22, 1949 2,485,621 McNairy Oct. 25, 1949 2,485,623 McNairy Oct. 25, 1949

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