Fluid handling – Line condition change responsive valves – With separate connected fluid reactor surface
Reexamination Certificate
2000-08-02
2001-12-25
Hepperle, Stephen (Department: 3753)
Fluid handling
Line condition change responsive valves
With separate connected fluid reactor surface
C137S554000
Reexamination Certificate
active
06332476
ABSTRACT:
PRIOR ART
The invention relates to a pressure level monitoring device.
Pressure level monitoring devices of this kind are usually used in the field of hydraulics or pneumatics in which there are used, for example, in control and switching units. In particular, in the automotive field, they are also used for monitoring tire pressure, in brake and injection systems, in door locking, and in seat adjustment.
The essential components of known pressure level monitoring devices are pressure switches which, together with check valves, permit the monitoring of pressure. The pressure switches are designed so that certain functions can be switched on as a function of pressure by means of positive or negative pressure on a membrane connected to a switching unit. The switching actuator moves in opposite directions depending on whether there is a positive or negative pressure and switches different electrical contacts.
Purely for the sake of pressure level monitoring, it is not necessary for there to be a switching as a function of positive and negative pressure, i.e. it is completely sufficient if only one electrical contact is switched. The use of conventional pressure switches consequently involves an unnecessarily high materials expense.
Furthermore, with conventional pressure switches, the check valves are not explicitly part of the switches, but are disposed separately on a component that is connected to the switches, for example a base plate or a control block.
Consequently, the utilization range of conventional pressure level monitoring devices is strictly limited because the desired function is only achieved together with an additional special component. Furthermore, a relatively high monetary and primarily materials-related expense is required, which additionally complicates the assembly of the switch used for pressure level monitoring.
SUMMARY OF THE INVENTION
The device according to the invention, has the advantage that conventional pressure switches, while at the same time reducing the number of components and therefore also reducing the number of assembly steps, are given an additional function which permits them to monitor and maintain a particular pressure level without depending on a special component. This is made possible through the integration of the check valve that communicates with the inner chamber of the housing into the bottom housing part.
Furthermore, the two-part embodiment of the housing with a top housing part and a bottom housing part results in a very compact design.
Advantageous updates and improvements of the device according to the invention, according to the main claim, are possible through the features embodied in the dependent claims.
The check valve integrated into the bottom housing part has a second membrane with a central opening and a securing means that fixes the second membrane. It is also respectively connected to at least one inlet fitting and one outlet fitting. This results in the fact that the pressure switch used for a particular task can be used universally and can be used for pressure level monitoring in other technical fields as well.
If the second membrane is secured along its edge region by the securing means against a shoulder inside the bottom housing part, then it is fixed with regard to its position in the bottom housing part and its position there cannot change, even under the influence of pressure. Moreover, if it is comprised of an elastic material, then only its central region will be deformed under the influence of pressure. When it is not deformed, the central region of this second membrane rests against a sealing surface which is formed onto a sealing seat embodied on the inside of the bottom housing part.
In order for this valve device to be able to function as a check valve, the second membrane divides the inner chamber of the housing, which can be acted on by a pressurized fluid, into three different subchambers. This results in an extremely compact design which permits the check valve function and the monitoring function to be provided in a compact space adjacent to each other and using the same components.
The first subchamber is essentially defined by the first membrane and the second membrane, the second subchamber is essentially defined by an outer wall containing the inlet fitting and the outer surface of the sealing seat together with the second membrane, and the third subchamber is essentially defined by the inner surface of the sealing seat together with the second membrane.
This prevents overpressure from escaping into the second subchamber from the first and third subchambers. At the same time, however, overpressure is prevented from escaping into the first and third subchambers from the second subchamber. The classic check function is therefore produced.
REFERENCES:
patent: 4140436 (1979-02-01), Schumacher
patent: 4247260 (1981-01-01), Schoenwald
patent: 4493339 (1985-01-01), Porter, Jr.
patent: 4754732 (1988-07-01), Kuczenski
patent: 4948931 (1990-08-01), Nixon
patent: 5144102 (1992-09-01), Buse
patent: 5620024 (1997-04-01), Yonezawa
patent: 43 42 587 A (1995-06-01), None
Bauer Bertram
Paessler Wolfgang
Hepperle Stephen
Robert & Bosch GmbH
Striker Michael J.
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