The present invention relates generally to laundry washing machines, and more particularly, to gravity drain laundry washing machines in which wash water drains from a wash tub by gravity under control of a drain valve.
Many large commercial laundry washer extractors utilize a gravity drain for draining water from the laundry wash tub following wash and rinse cycles. In such washing machines there is no electric pump for forcing the water from the laundry machine, but instead, water flows by gravity to a drain, normally in the floor of the laundry facility.
In such gravity drain washing machines, a drain valve is provided that is closed to retain water within the wash tub during the washing cycle, and an electric motor is provided to control opening and closing of the valve. Heretofore, such drain valves have had poor reliability due to excessive variability in the forces required to open and close the valve. Drain valves with a rotatable ball design are particularly problem prone due to the sliding nature of the ball that results in the valve sticking and not fully closing due to wear or contaminants and corrosive chemicals in the wash water. Flapper style drain valves which utilize a flapper plate that is pivoted between open and closed positions have been utilized in an effort to eliminate relative sliding movement of the valve components and the resulting variability in the opening and closing forces of ball valves. Such flapper style dump valves, however, require relatively high torque motors for maintaining the required sealing force on the flapper plate and can be subject to leakage due to poor sealing contact.
It is object of the present invention to provide a gravity drain laundry washing machine with a drain valve adapted for more reliably controlling the retention and discharge of wash water used during washing cycles.
Another object is to provide a gravity drain laundry machine as characterized above which has a flapper style drain valve adapted for reliable operation with a lower torque motor.
A further object is to provide a gravity drain washing machine with a flapper style drain valve of the above kind effective for more reliably maintaining the flapper valve in a closed condition, while minimizing the required torque of the electric control motor.
Still another object is to provide a gravity drain washing machine with a flapper style drain valve of the foregoing type adapted for more effectively sealing the flapper plate in a closed position.
Yet another object is to provide a laundry machine with such a drain valve which is relatively simple in design and lends itself to economical manufacture.
Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings, in which:
While the invention is susceptible of various modifications and alternative constructions, a certain illustrative embodiment thereof has been shown in the drawings and will be described below in detail. It should be understood, however, that there is no intention to limit the invention to the specific form disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention.
Referring now more particularly to
In accordance to the invention, the drain valve has a flapper design effective for more reliable trouble-free operation. In the illustrated embodiment, the drain valve 11 has a housing 25 which comprises a central body portion 26 with an inlet port 28 coupled to the wash tub outlet piping 20 and an outlet port 29 coupled to the drain piping 21. The drain valve 11 defines a liquid flow passage 27 between the inlet and outlet ports 28, 29 and includes a flapper plate 30 mounted for pivotable movement about an upper end between a closing position for blocking the flow of liquid from the washer tub 14 through the drain valve 11 and a raised open position for permitting the discharge of water by gravity from the washing machine to the drain piping 21. The illustrated flapper plate 30 is disposed adjacent a downstream end of the inlet port 28 of the valve housing 25 for closing the inlet port 28 when in the closed position. The flapper plate 30 in this case has a molded plastic construction with integral support shaft segments 31a, 31b extending outwardly from opposite top sides of the flapper plate 30. It will be understood that while the illustrated flapper plate 30 has integrally-formed shaft segments 31a, 31b, alternatively, the flapper plate could be fixedly mounted on a separate and discrete pivot shaft.
For rotatably supporting the flapper plate 30 for pivotal movement relative to the housing 25, in this case one of the opposed shaft segments 31a is rotatably supported within a bushing 34 mounted in a cylindrical opening 35a on one side of the housing 25 (
For pivoting the flapper plate from the open position to the closed position, a drain valve motor 50 is mounted on a side of the valve housing 25, which may be a conventional electric gear motor with an output shaft 50a (
In keeping with the invention, the drain valve motor 50 is operable through linkage which pivots the flapper plate 30 between open and closed positions as an incident to operation of the motor 50 and which more effectively retains the flapper plate 30 in closed sealed relation to the inlet port 28. To this end, in the illustrated embodiment, the drain valve motor output shaft 50a has a crank arm 55 having an outer end pivotably coupled to an outer end of the flapper plate crank arm 41 through an intermediate pivot link 56. The motor output shaft 50a, has a keyed connection with a hub 58 of the motor crank arm 55, in this case, including a radial key 60 positioned within a complementary radially oriented key receiving slot 61 in the hub 58. (
When the flapper plate 30 is in the open position, as shown in
As can be seen with reference to
For enhancing sealing contact between the flapper plate 30 and the inlet port 28 when the flapper plate 30 is in a closed position, the flapper plate 30 has a plastic sealing member 72 about the side facing the inlet port 28. The sealing member 72 in this case is in the form of a flat molded plastic annular member having rearwardly extending barbs 74 about its periphery for removable engagement within arcuate slots 75 formed in the molded plastic flapper plate 30 (
For pivoting the flapper plate 30 from the vertical closed position to an upwardly pivoted open position for enabling water within the washing machine to drain through the drain valve 11 to the drain piping 21, a torsion spring 75 in this case is provided for biasing the flapper plate 30 to the raised position. In this case, a torsion spring 75 has a cylindrical coil section 75a disposed about the gear motor crank arm hub 58, with one end fixed about the motor crank arm 55 and the other end biased against a stop pin 76 fixed to the mounting plate 51 (
In carrying out a further feature of the illustrated embodiment, the drain valve 11 is designed for enabling the drain valve motor 50 to be mounted on either side of the drain valve housing 25 in order to facilitate mounting in washing machines of different configurations. To this end, in the illustrated embodiment, the shaft segments 31a, 31b of the flapper plate 30 are identical in form, each having a radial drive key 42 for enabling a keyed connection with the socket or hub 40 of the flapper plate crank arm 41, depending upon the side of the drain valve 11 upon which the motor 50 is mounted. The bushing 34 has a cylindrical internal diameter for rotatably supporting either shaft segment 31a, 31b, of the flapper plate 30, depending upon the mounting position of the drive motor 50.
It will be appreciated by one skilled in the art that the drain valve 11 in accordance with the invention is relatively simple in design and adapted for economical manufacture. Effective sealing and retention of the flapper plate 30 in the closed position is effected without substantially increasing the torque requirement of the drain valve motor 50. In practice, reliable operation can be achieved by utilizing a conventional shaded pole a/c gear motor having output shaft speed of between 18 and 30 rpm, a minimum starting torque of 3.5 inch pounds, and a running torque of between 14 and 20 inch pounds. The flapper plate 30, motor and flapper crank arms 55, 41 and the intermediate link 50 also all may be economically formed by plastic injection molding. A plastic material, such as commercially available plastic sold under the tradename “A Model A-1145HS”, may be used, which is chemical resistant, rigid, and heat resistant sufficient to withstand loads when exposed to water temperatures up to 195° F. The flapper plate 30 in this case also is formed with a plurality of laterally spaced recesses 80 between the shaft segments 31a, 31b to reduce material and a plurality of elongated central recesses 81 which both reduce material and define reinforcing rigs of the flapper plate 30. Hence, it can be seen from the foregoing that a washing machine with a flapper style gravity drain valve is provided that is adapted for reliable operation with a lower torque motor and which has a simple and versatile design which lends itself to economical manufacture.