Patent Application
20090211955
An anti-drainback valve (ADB) is a type of valve that is typically a component in spin-on oil and fuel filters. An ADB, when used in conjunction with oil filters, is designed to retain oil in a filter and to prevent the filter from being drained when the engine is not running. This ensures that the oil can achieve its full lubricating effect as soon as the engine is started.
ADBs are typically made from rubber. Rubber ADBs are often molded in silicon, nitrile, or other suitable rubber compounds in a two-part opening mold. A two-part mold is typically used for manufacturing ADBs because it is a cost-efficient process for producing a large quantity of ADBs based on their symmetrical shape.
Larger conventional spin-on filter assemblies typically employ ADBs that fit on a cap with a collared-type design. Such larger conventional filter assemblies are often used in locations where space restrictions are not an issue. An example of a large conventional filter assembly that utilizes a collar design can be found in U.S. Pat. No. 3,339,738.
There are certain situations and designs, however, that allow only for a very limited space for installing ADBs on oil and fuel filters in an engine. For example, engines on newer cars produced by companies such as Honda, Nissan, and Toyota have very limited space (about 75 to 90 mm) for mounting 65 mm diameter oil filters. Such space limitations have resulted in a difficulty in the installation of the conventional ADBs that utilize a collared cap design.
Plain caps (i.e., caps with relatively flat tops) have been designed for use on filter assemblies with tighter space limitations. Conventional ADBs used on filter assemblies utilizing such plain caps, however, do not lock into the caps securely. As a result, conventional ADBs may slip from the caps of the filter assemblies in rapid production assembly lines. This can cause a slowdown in production, and may even require a 100% inspection rate to ensure that slipped ADB filters do not reach customers.
An improved anti-drainback valve that may be used in plain-cap fittings of filter assemblies is described.
According to one aspect of the present invention, keys are added to ADBs. The keys extend past the cap of the filter assembly to secure the valves into place. The keys provide for adequate locking, as well as ease of installation and removal of the valves.
An advantage of the locking features of the present invention is keeping manufacturing costs low. The ADBs using the locking features of the present invention may be manufactured by utilizing a two-part mold. Additionally, the present invention does not require a significant amount of additional material compared to conventional ADBs.
The invention is to be explained in more detail below based on embodiments depicted in the following figures where:
a is a cross-sectional side view of a filter assembly utilizing an ADB containing an embodiment of the locking features of the present invention, where the ADB is closed;
b is another cross-sectional side view of an filter assembly utilizing an ADB utilizing an embodiment of the locking features of the present invention, where the ADB is open;
c is a cross-sectional side view of a portion of the filter assembly utilizing an ADB utilizing an embodiment of the locking features of the present invention;
A conventional ADB that is typically used with plain cap fitting of a filter assembly is illustrated in
The conventional ADB 101 that sits within the cap 103 is not held within the filter assembly 102 in a secure fashion. If under any circumstances the ADB slips away from the cap during assembly of the filter, the ADB does not function as intended.
a, 2b, and 2c illustrate cross sections of a preferred embodiment of the filter assembly utilizing an improved ADB in accordance with the present invention. The ADB 1, containing at least two keys 2, sits within a plain cap 4. The cap 4 covers the filter medium 3 and filter chamber 5. Upon installation of the ADB 1, the at least two keys 2 extend past the cap 4 of the filter assembly and secure the ADB 1 into place. A reinforcing plate 8 contains a threaded outlet 9 to enable the filter assembly 6 to be mounted on a thread stud on the engine base (not shown) or suitable mounting arrangement per individual vehicle/engine design.
a and 2b illustrate the functionality of the ADB 1 as used within the filter assembly 6.
With reference to
When an engine/pump is turned on, the oil under pressure pushes the conical lip 7 inwards and the oil begins flowing into the filter assembly and through the filter medium via path B in the filter medium 3 (as illustrated in
Based on the functionality described, the oil filter retains oil on its dirty side (unfiltered side) when the ADB is closed and prevents the air traps in the oil circulation cycle. Other components and functionality of typical oil filters have been previously described in, for example, U.S. Pat. No. 7,168,572, which is hereby incorporated by reference in its entirety.
Although three keys are considered as the preferred embodiment because of design simplicity and ease of manufacturing, it is expressly contemplated that any suitable number of keys 2 may be used. In those alternative embodiments, the keys are preferably approximately equally distributed throughout the circumference of the cap, as is shown with the keys of the preferred embodiment shown in
As
A cross sectional side view of an exemplary key 11 is shown in
One factor in determining the proper taper angle for the key is to determine the shape of the key that would cause the ADB to be properly secured within the cap of the filter assembly. For example, a smaller angle may be preferable when using an elongated key, and larger angles may be preferable when using a shorter key. An angle significantly larger than the preferred range, however, may result in difficulty installing the ADBs. In contrast, an angle that is too small may result in a key that would not even contact the sides of the cap to enable locking.
The key 11 has rounded edges 12 and 13, which may allow for easier installation and removal of the ADBs into the filter. The key 11 also contains a circumferential ridge 14 for securing the key in place.
As shown in
Similarly, the key may utilize a shape that does not utilize a taper angle as described above. For example, the key may have a circular or elliptical shape.
A selection of an alternative design may be decided as a matter of design choice, or it may be dictated based upon the design features of the particular filter assembly that the ADB will be used with.
The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be-construed to include everything within the scope of the appended claims and equivalents thereof.
