Fluid handling – Systems – Multi-way valve unit
Reexamination Certificate
2000-05-09
2001-12-11
Michalsky, Gerald A. (Department: 3753)
Fluid handling
Systems
Multi-way valve unit
C074S110000, C251S089000, C251S294000
Reexamination Certificate
active
06328068
ABSTRACT:
FIELD OF THE INVENTION
The present invention is directed to a push-pull coupling. More particularly, the present invention is directed to a push-pull coupling adapted to connect an operator to a device in both a push and a pull direction as well as to mechanically disconnect the operator from the device.
BACKGROUND OF THE INVENTION
It is frequently necessary or desirable to selectively couple and uncouple an operator from a device. A particular application of this coupling need is in hydraulic machines such as skid-steer loaders and other hydraulic devices which may have other functions, such as but not limited to, street sweepers, ground boring machines, bull dozers, graders and earth scoopers. It is necessary to enable hydraulic systems, such as hydraulic lifts, only when a person is seated on the machine. In the past, this has been done by a solenoid operated lock pin which prevents operation of a valve spool by engaging a groove in the spool to retain the spool in a neutral position. Due to tolerance stack-ups, if an operating lever is pushed hard enough, the device can receive a small amount of oil and creep instead of remaining in position. Moreover, this type of solenoid spool lock requires that the operating handle be returned to neutral before the lock pin re-engages the groove in the spool. This leads to dangerous conditions in which the hydraulic device moves or operates when the lock pin should be engaged. A primary drawback of the solenoid projected lock pin is that the operating handle is always positively connected to the spool and will apply a longitudinal force to the spool whenever the actuating lever is pushed or pulled. It is therefore necessary to rely on the interference of the lock pin in order to prevent operation of the hydraulic device.
Hydraulic machines are exemplary of devices having safety features which disabled the machines under certain circumstances. There are numerous other devices which employ safety devices that have drawbacks which may be similar, analogous or in addition to the afore-discussed drawbacks of solenoid operated locking pins.
The difficulties are especially acute when it is necessary to prevent the operation of a device which moves in both directions, i.e., a device which is both pushed and pulled during its operation.
In view of these and other considerations, there is a need for improving the reliability and safety of devices which utilize push-pull operators.
SUMMARY OF THE INVENTION
The present invention relates to a push-pull coupling adapted to connect an operator to a device for moving the device in both push and pull directions. The invention comprises a body having first and second ends. A rod is disposed at the first end of the body and is mounted for slidable movement with respect to the body in both the push and pull directions, the rod being adapted to positively connect to the operator. A connector is located at the second end of the body and is adapted to positively connect the body to the device. A lost motion connection is disposed between the rod and the connector. The lost motion connection has a first mode in which there is a de-coupling of the rod to the connector resulting in lost mechanical motion in both the push and pull directions. The lost motion connection further has a second mode in which there is a positive coupling between the rod and the connector, wherein motion of the rod is transmitted to the connector. An electromagnetic actuator is associated with the lost motion connection for maintaining the lost motion connection in the first mode when deenergized and for maintaining the lost motion connection in the second mode when energized.
In a more specific aspect, the lost motion connection of the push-pull coupling includes first and second armatures. The first armature is positively connected to the push-pull rod only when the rod is pulled and is disconnected from the rod when the rod is pushed. The second armature is positively connected to the push-pull rod when the rod is pushed and disconnected from the rod when the rod is pulled. The electromagnetic actuator functions to disconnect both armatures from the body when in the first mode and for connecting both armatures to the body when in the second mode by applying electric current to electromagnets disposed within the body.
In a further aspect of the invention, first and second springs are provided for biasing armatures to the first positions in which the armatures are disconnectable from the coils of the electromagnets when the electromagnetic actuator is in the first mode and wherein the armatures positively couple with the coils when the electromagnetic actuator is in the second mode, whereby the armatures are disconnected from the body when the lost motion connection is in the first mode and are positively connected to the body when the lost motion connection is in the second mode.
In a still further aspect of the invention, the body is in the form of a housing having a connector at one end, and the push-pull rod at the other end with the armatures, electromagnets and springs disposed within the body.
In one application of the invention, the push-pull coupling is disposed between the spool of a hydraulic valve and an operator for that valve and enables reciprocation of the spool within the valve only when the electromagnetic actuator is energized, thus providing a safety device which in a specific aspect enables reciprocation of the spool only when the person operating the valve is correctly positioned to manipulate the operator, such as being seated on a seat which closes a switch that energizes the electromagnetic operator.
REFERENCES:
patent: 4019602 (1977-04-01), Habiger
Dana Corporation
Michalsky Gerald A.
Millen White Zelano & Branigan P.C.
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