BACKGROUND OF THE INVENTION

The present invention relates to an improved oil filter construction for oleodynamic applications and lubricating-refrigerating circuits in general.

As is known, an oil filter is generally used in oleodynamic lubricating and/or refrigerating circuits, to collect oil polluting solid contaminating materials, during a normal operation of a related system or machine.

A conventionally used oil filter comprises a metal body which may be directly screwed on a block integral with the system or machine and containing the filtering element.

The so-called "spin-on" filters are usually of a disposable type, and have the great drawback that they are difficult to be disposed of.

SUMMARY OF THE INVENTION

The aim of the present invention is to provide such on oil filter construction, for oleodynamic applications and lubricating/refrigerating circuits, which may be easily disposed of.

Within the scope of the above mentioned aim, a main object of the present invention is to provide such an oil filter construction which may be used in place of conventional "spin-on" filters, disposable screwing-on filters.

Another important object of the present invention is to provide such an improved oil filter construction which may be easily constructed on an industrial scale, and which, moreover, is very competitive from a mere economic standpoint.

Yet another object of the present invention is to provide such an oil filter construction which, owing to its specifically designed operating structures, is very reliable and safe in operation.

According to one aspect of the present invention, the above mentioned aim and objects, as well as yet other objects, which will become more apparent hereinafter, are achieved by an oil filter construction for oleodynamic applications and lubricating and refrigerating circuits in general, characterized in that said oil filter construction comprises a filtering core engaged in a container body which is closed at a top thereof by a closing flange with which is associated a hub element, without any possibility of turning between the flange and the hub element; said hub element being arranged between said flange and the filtering core; said container body being coupled to said flange by coupling means allowing to detach said body from said flange in order to withdraw said filtering core and separately dispose of said filtering core.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the present invention will become more apparent hereinafter from the following disclosure of a preferred, though not exclusive, embodiment of the invention which is illustrated, by way of an indicative but not limitative example, in the accompanying drawings, where:

Figure 1 is a perspective view of the inventive improved oil construction, being shown in an assembled condition and ready to be installed;

Figure 2 is an exploded perspective view of the above oil filter construction; Figure 3 is a perspective view of the flange;

Figure 4 is a perspective view of the container body;

Figure 5 is a longitudinally cross-sectioned perspective view showing a coupling zone between the flange, the hub element and the container body;

Figure 6 is a partially cross-sectioned elevation view showing the coupling zone between the flange, the hub element and the container body;

Figure 7 is a cross-sectioned perspective view showing the inner part of the flange;

Figure 8 is a cross-sectioned side view of the flange; and

Figure 9 is a perspective view showing a top portion of the container. DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the number references of the above mentioned figures, the improved oil filter construction according to the present invention, generally indicated by the reference number 1 , comprises a filtering core 2 engaged in a container body 3 which is closed at a top thereof by a closing flange 4.

A hub element 5 is associated with said flange 4, in a non-rotary manner, and being arranged between said flange and the filtering core 2.

The container body 3 is coupled to the flange 4 by quick coupling or connecting means, advantageously comprising a bayonet attachment assembly.

The hub element 5 is coupled to said flange 4 by ridges 6 formed on said flange, and corresponding recesses 7 formed in the hub element 5.

The ridges 6 of the flange 4 engage the recesses 7 of the hub element 5, thereby making said flange and hub element rotatively rigid, to allow in turn a clamping or disassembling torque of the overall filter to be transmitted.

The three ridges 6 of the flange 4 and the corresponding three recesses 7 on the hub element 5 are preferably arranged with a 120° arrangement, and their geometrical configuration is such as to prevent the mentioned two components from being improperly assembled.

The assembling torque may be transmitted only by a proper mutual engagement of the two parts; in fact, in a different condition, the two components would be disengaged from each other and an operator would immediately detect the assembling problem, since he would not be able to properly screw-on the filter.

In this connection it should be pointed out that, from a filter functional standpoint, it is not necessary to provide a hydraulic sealing between the flange and the hub element; in fact, any possible leakage will in any case remain on the "dirty" side of the filter, that is upstream of the filtering element proper 2.

The bayonet coupling between the container body 3 and the flange 4 is advantageously made by three outer radially extending ridges 8, formed on the container body 3, and arranged with a 120° arrangement from one another, and three corresponding recesses or cavities 9 formed in the flange body 4 and being defined by corresponding peripheral ridges 10. The peripheral ridges 10 of the flange 4 snap engage in corresponding recesses 11 formed on the container body 3 at the mentioned outer ridges 8.

Said snap engaging element system is advantageously arranged in that part of the flange nearest to the thick and radiused region thereof, in order to minimize a stress status induced by the system of forces operating on the tooth elements of the snap coupling assembly, as the filter is in a pressurized condition.

Such a snap engaging element system facilitates the filter assembling, as it will be disclosed in a more detailed manner hereinafter.

The sealing between the flange 4 and the container body 3 is achieved by an O-ring 12, engaged in an annular cavity or recess integrally formed on the container body 3.

The sealing surface of the flange may be made, for example, by a turning mechanical machining operation, or in other desired manners on the raw surface of said flange, thereby avoiding the machining costs.

Said sealing system is a particular efficient one with respect to the cyclic stress and strain forces operating on the filter components.

A second O-ring 13 is arranged between the hub element 5 and the filtering core 2.

In a use condition, that it with the body 3 being latched or coupled to the flange 4, a pressing spring, arranged between a bottom of the body 3 and the filtering core 2, will press the latter against the hub element 5, thereby pressing the second O-ring 13 to provide a proper sealing between the filtering core 2 and the hub element 5.

As shown, said hub element 5 comprises a threaded hole 14 engageable by the threaded attachment zone (nipple) provided on a standard type of filter housing.

Oil to be filtered, coming from the system or machine to which the filter is assembled, enters the filter body through a plurality of slots 15 formed through the hub element 5.

Said oil is filtered as it passes through the filtering core 2 septum, with a radial direction with respect to the filter axis. The polluting material particles will be restrained by the filtering core 2 septum. The filtered oil, in turn, flows through the inner volume of the filtering core 2 and may return to the system or machine through the threaded hole 14, as engaged on the filter attachment assembly, not shown in the figures, provided in the system or machine casing.

As shown, the flange 4 comprises an outer annular cavity or recess 16 designed for engaging therein a sealing gasket 17, of any desired standard type, allowing the filter construction to be properly tightly mounted to the casing of the system or machine on which is installed.

The first assembling of the filter construction according to the present invention is made as follows.

In an assembled condition, shown in Figure 1 , the filter construction is similar to a conventional "spin-on" filter, of a disposable type, and accordingly may be interchanged with a conventional filter without any operating problems.

By gripping the container body 3, it is caused to be screwed on the male threaded attachment portion (nipple) being rigid with the motor or machine on which the oil filter must be installed.

It would be possible, and preferred, to perform the screwing on and clamping in a manual manner, or provide a torque closing by using a torque wrench, to be engaged in the recessed hexagonal arrangement formed in the cap of the filter container 3.

Upon clamping, the flange will provide a preloading of its outer gasket 17 on the housing or casing.

For subsequent filter maintenance operations, involving only a replacement of the filtering element 2, it will not be necessary to screw off the flange 4, but the bayonet coupling system will be exploited as disclosed hereinafter.

A periodic maintenance of the filter, that is the replacement of its filtering element, will be performed as follows.

The mentioned bayonet engagement system comprises a limit stop restraining system; thus, to disassemble only the filter container 3, an operator will operate as follows.

He will provide a pressure on the container 3 cap in a direction of the filter flange; this pressure will provide a corresponding related movement of the container 3 toward the flange 4, thereby allowing the bayonet assembly tooth elements to be disengaged.

While continuing providing the axial force, a rotary torque in a clockwise direction is applied; as the male and female tooth elements of the container 3 and flange 4 are arranged in a mutual disengagement position, as defined by the limit stop contacts, then the container may be removed by pulling it in the filter axis direction.

Thus the container body 3 will be gripped by the operator hand, with the filtering core 2 arranged therewithin: in such a condition it will be possible to replace the filtering core 2, by arranging a new filtering core 2 on the counterbiasing spring, provided in the cap of the container 3.

Together with the new filtering element 2, two replacement sealing O-rings 12 and 13 will be also supplied, one of which arranged between the container 3 and the flange 4, and the other between the filtering element 2 and the hub element 5.

The filter reassembling will be performed by a reversed operation sequence compared to that hereinabove disclosed: plugging-in by an axial engagement, mutually engaging the bayonet tooth elements, applying a clockwise plug-in torque, up to the limit stop position, then releasing.

During the application of the plug-in torque, the inclined surfaces of the bayonet tooth elements will cause a raising or lifting of the container 3, while transforming an applied torque into a flange inserting pulling force, so as to overcome the friction of fitting the O-ring 12 between the flange 4 and the container 3 as well as the counterbiasing force provided by the inner spring.

In the releasing step, the two portions, that it the container 3 and the flange

4, will be brought again to the anti-screwing off position, with the anti-screwing off ridges in a mutual engagement condition.

It has been found that the invention fully achieves the intended aim and objects.

In fact, the invention has provided an improved oil filter construction, allowing the filtering element, disengaged from its containing body, to be easily disposed of. Moreover, the improved oil filter construction according to the present invention is more advantageous from a product making standpoint.

In practicing the invention, the materials used, as well as the contingent size and shapes, can be any, according to requirements.