Cleaning and liquid contact with solids – Apparatus – Miscellaneous
Reexamination Certificate
2000-11-21
2002-11-26
Stinson, Frankie L. (Department: 1746)
Cleaning and liquid contact with solids
Apparatus
Miscellaneous
C068S0030SS, C068S184000
Reexamination Certificate
active
06484738
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to dishwashing equipment and more particularly to a dishwashing machine which is specially constructed to provide easy removal of the pump/motor unit for servicing.
BACKGROUND OF THE INVENTION
In dishwashing machines used in restaurants and other commercial and institutional facilities, the liquid for washing and rinsing the dishware is applied by one or more spray arms. A pump driven by an electric motor supplies the liquid to the spray arms. There are various types of dishwashing machines that are used in this type of application, including conveyor machines, self standing machines and under counter machines. In each type of machine, the motor is the subject of the majority of service calls.
Removing and servicing the motor is a major maintenance undertaking. The motor is usually bolted to the pump and bolted down to the cabinet frame, typically in the back corner area of a motor compartment located at the bottom of the dishwasher cabinet. In order to remove the pump and motor as a unit, it is necessary to disconnect the inlet and discharge piping leading to and from the pump, which is a difficult task in itself. Then, the bolts securing the motor to the cabinet must be reached and removed to release the motor. Electrical wiring must also be disconnected or otherwise dealt with. Because the motor typically weighs 50 pounds or more, it is difficult to lift out of the cabinet even after it has been disconnected. Access to the bolts for the motor is impaired because the most practical location for the motor is in the back corner area of the motor compartment. In addition, there are numerous other components located in the motor compartment, and they must be worked around and cleared when the motor is pulled out. Adding to the accessibility problem is the common practice of installing the dishwasher under counters or tables that may extend up to two feet or more beyond the dishwasher cabinet. Often, large tables must be disassembled and components such as large scrap boxes must be taken out of the dishwasher cabinet in order to provide room to remove the motor.
At best, service personnel must work on their backs or in another awkward position and try to disconnect the piping, reach the motor mounting bolts to loosen them, and then remove the 50 pound motor for servicing, all while working around obstacles such as hoses, electrical wires, plumbing fittings and scrap boxes. In some cases, the motor can be disconnected from the pump in order to avoid the need to disconnect the piping. However, the bolts that connect the pump to the motor are usually even more difficult to reach while the pump/motor unit is in place. Even if a worker is able to reach and remove the bolts, the motor still must clear the pump in order to allow it to be removed, and the problems of lifting a heavy motor from a relatively inaccessible location are still encountered. Also, it is not always known in advance whether the problem is with the pump or the motor, so both must usually be removed.
The motor can be bolted to hanger straps instead of being bolted down to the cabinet floor. However, the bolts still must be removed, and their accessibility is no easier in a hanging installation than in a bolted down installation. Additionally, the heavy motor must be temporarily supported by blocking or in some other manner so that it will not fall when disconnected from the strapping. Setting up temporary blocking under the motor in a relatively inaccessible location is a difficult task.
After the motor has been removed and repaired or replaced, it must be installed again in the dishwasher cabinet. This can involve even more time and difficulty than its removal. It is not uncommon for the plumbing system to be reconnected improperly or for another mistake to be made that can cause even greater problems and additional down time of the machine. It is typical for one or two hours to be required for removal of the motor and as much or more time to be required to install it after it has been serviced or replaced. In corner areas of counters where disassembly of the counter structure or tables is necessary, up to one-half day can be involved in removing the motor. As can easily be appreciated, this can be a serious detriment to the efficient operation of a restaurant or other facility that has great difficulty going without a dishwasher for time periods this long.
SUMMARY OF THE INVENTION
The present invention is directed to a dishwasher in which the pump/motor unit can be removed more quickly and easily than has been possible in the past. In comparison with existing machines that require up to one-half day for removal of the motor, the pump/motor of the present invention can be removed even by unskilled personnel in 10 minutes at the most.
In accordance with a preferred embodiment of the invention, the pump/motor unit of a dishwashing machine is provided with a base that is mounted on a track along which the pump/motor can slide when it needs to be removed for servicing. The inlet and discharge pipes for the pump are equipped with special quick disconnect couplings that effect watertight seals and yet can be quickly detached so that the motor can be removed. The couplings may include sleeves that normally fit around the pipe joints with adjacent pipes butted together end to end. The sleeves are tightened by clamps which are secured by nuts and bolts. When the bolts are loosened, the couplings can be slid off the end of one pipe to disconnect adjacent pipes and allow the motor to slide out along the track. The track is strategically located and oriented where it allows the pump motor to be mounted in the back corner area of the dishwasher cabinet and yet slide out to the center of the cabinet so it can clear obstacles such as scrap trap boxes and other components in the motor compartment. This is achieved by angling the track from the back corner toward the center of the front of the cabinet where the pump/motor can be most easily lifted out of the machine and most easily replaced after it has been serviced.
Other and further objects of the invention, together with the features of novelty appurtenant thereto, will appear in the course of the following description.
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Andrews James T.
Payzant Russell L.
Shook, Hardy & Bacon, LL
TCA, Inc.
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