Fluid handling – With cleaner – lubrication added to fluid or liquid sealing...
Reexamination Certificate
2002-02-15
2004-12-21
Walton, George L. (Department: 3753)
Fluid handling
With cleaner, lubrication added to fluid or liquid sealing...
C073S001720, C073S001740, C073S861000, C137S487500, C137S554000, C137S557000, C184S006230, C184S007400, C184S055200, C222S056000, C222S262000, C222S309000, C340S606000, C340S611000, C417S063000, C417S401000, C417S553000, C700S282000, C700S283000, C702S047000, C702S055000, C702S057000, C702S100000
Reexamination Certificate
active
06832620
ABSTRACT:
PRIORITY CLAIM
This application is based on and claims the priority under 35 U.S.C. §119 of German Patent Application 101 07 558, filed on Feb. 17, 2001, the entire disclosure of which is incorporated herein by reference.
FIELD OF THE INVENTION
The invention relates to an apparatus for dosing a lubricant such as oil, grease or the like into a compressed air line, whereby the apparatus includes a lubricant container, a lubricant pump, and at least one valve.
BACKGROUND INFORMATION
A great variety of different dosing devices are known in the prior art, for dosing or dispensing small controlled quantities of lubricant into a compressed air line, for example. Such dosing devices are also known as injection oilers or minimum quantity dosing systems. The general technology of these systems is based on an air injection and spraying system, wherein a predetermined quantity of a lubricant is injected into a compressed air flow, by which the lubricant is then sprayed or blown with a suitable pressure onto the machine part or other component that is to be lubricated. Such lubricant dosing devices are used for a variety of different applications in a variety of different fields. Examples of dosing devices of this kind are sold commercially in ordinary trade by the company Willy Vogel AG, Berlin, Germany.
All conventionally available dosing systems of the above described general type usually have many features and parameters that can be adjusted by the user or operating personnel, for example offering the possibility of adjusting the quantity of lubricant to be injected during each dosing cycle. In view of this broad adjustability, it is possible to make faulty or improper adjustments, and to mechanically tamper with the device. That very easily leads to operating errors, so that a reliable and proper lubricating operation cannot be ensured. Moreover, monitoring and controlling the proper functionality, and recognizing any arising errors or faults during the lubricating process is not possible, or is only possible with considerable technical efforts.
Overall, the handling, error monitoring, identification and correction, the great number of individual parts, and the complicated arrangement and connection of the various lines or conduits of such conventionally available systems are not suitable for reliably achieving a minimum error rate. Depending on the particular application, a defect of the dosing system which causes an improper or inadequate lubrication can lead to faulty operation or even a total failure and breakdown of the apparatus or machine that is to be lubricated by the dosing system.
SUMMARY OF THE INVENTION
In view of the above, it is an object of the invention to further develop and improve a lubricant dosing apparatus of the above described general type, to achieve a simpler and better operating comfort, and to reliably avoid faulty and erroneous operation thereof. Another, more particular object of the invention is to provide a reliable indication of the proper or improper operation of the dosing apparatus, in a simple manner. The invention further aims to avoid or overcome the disadvantages of the prior int art, and to achieve additional advantages, as apparent from the present specification.
The above objects have been achieved according to the invention in a lubricant dosing apparatus for providing a dosed supply of a lubricant into a pressurized air flow. The apparatus includes a lubricant container, a pneumatically actuated lubricant pump, a lubricant injection channel selectively communicating with an outlet of the lubricant pump, a non-return or one-way check valve interposed between the outlet of the lubricant pump and the injection channel, and an electronic sensor that cooperates or is coupled (e.g. electromagnetically or mechanically) with the non-return valve in such a manner so that the sensor emits an electrical signal responsive to the position or movement of the non-return valve through a defined stroke. When the lubricant pump injects a properly dosed or metered quantity of the lubricant through the pump outlet, the pressurized lubricant temporarily pushes against and opens the non-return valve, causing this valve and particularly its valve stem to move through a resulting stroke with a resulting motion pattern and duration. The motion of the non-return valve stem is indicated by the electrical signal emitted by the sensor, and can be evaluated, e.g. by comparing it to proper signal level thresholds, time points, and/or durations, to determine whether the lubricant dosing operation was carried out properly, i.e. within proper parameters. A faulty operation recognized by this signal evaluation can be used to trigger a fault indication to operating personnel, or to shut down the system.
Thus, the basic feature of the invention is that the non-return valve is coupled with the electronic sensor in such a manner, so that the sensor will emit a corresponding electrical signal when the non-return valve carries out a defined stroke motion. The electrical signal is provided to a control and/or evaluating unit to be evaluated therein, so as to indicate either a successfully and properly completed lubricant dosing and injection cycle, or a fault condition.
In a preferred embodiment, the lubricant pump is embodied as a piston pump, with a dosing needle that is axially slidably guided in a needle bushing, and that withdraws a defined quantity of the lubricant out of the lubricant container via a throughflow port, and then injects this dosed quantity of lubricant into the injection channel, on each working stroke of the pump. The respective dosed and injected quantity of the lubricant is set and fixed (e.g. by the dimensions of the bore of the needle bushing and the stroke travel distance of the dosing needle), for example by the manufacturer of the device. Therefore, the per-stroke injection quantity is not readily externally adjustable (but would require, e.g., replacing the needle and the needle bushing with differently dimensioned components). Thereby, the possibility of an erroneous adjustment of the dosing quantity is avoided. Instead, the desired supply quantity of the lubricant can be electronically controlled, for example by controlling the frequency of dosing injection cycles.
The piston of the lubricant pump is pre-stressed by a compression spring in its neutral or resting position. The spring constant of this compression spring is selected in such a manner, so that the piston can only be moved from the neutral resting position into the working position (or “cocked” position), against the force of the spring, once a sufficiently high pre-defined air pressure has been applied to the piston. Then, when the supply of pressurized air is discontinued and the pressure is released, the spring force will return the piston from the working position to the resting position, thereby carrying out a working or injection stroke. Due to this spring-force actuation of the piston during the injection stroke, a constant injection pressure will always be ensured and (unlike air-pressure actuated pumps) will not be dependent on the pressure of the compressed air system, which is subject to fluctuations and varying adjustments. This, together with the abovementioned fixed prescribed lubricant quantity supplied in each injection cycle ensures a relatively consistent stroke of the non-return valve, as long as the viscosity of the lubricant does not vary substantially.
Moreover, since the supplied compressed air must have a sufficient pressure to overcome the constant spring force, for drawing back the lubricant pump piston, a leak or pressure drop in the compressed air system will be readily indicated and recognized in the inventive apparatus, as follows. With an inadequate actuating pressure, the piston of the lubricant pump would not have been drawn back (or “cocked”) at all, or would only have been drawn back partially. As a result, the injection stroke would not be carried out at all or only partially, whereby particularly the non-return valve would not move at all or would mo
Fasse W. F.
Fasse W. G.
Lindauer Dornier Gesellschaft mbH
Walton George L.
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