AIR FILTER FOR INDUSTRIAL VEHICLES EQUIPPED WITH POLYURETHANE END CAPS AND PROCESS FOR MANUFACTURING SAID FILTER

Abstract: An air filter (1) for industrial vehicles is described comprising a central sleeve (3); air filtering means (5) around the sleeve (3); a case (7) around the filtering means (5); an upper bottom (9) of the case (7) made of polyurethane and containing inside a support member (11) made of metal or polyurethane with greater hardness; and a lower bottom (13), also preferably made of polyurethane. This air filter (1) realizes an optimum air seal and deadens noises due to filter vibrations.

Description: AIRFILTERFOR INDUSTRIALVEHICLESEQUIPPEDWITHPOLYURETHANEENDCAPS AND PROCESS FOR MANUFACTURINGSAIDFILTER The present invention relates to an air filter for industrial vehicles equipped with at least one polyurethane bottom, and to a process for manufacturing such filter. Various type of air filters for industrial vehicles are known in the art, and they all have a filtering pack enclosed in a drilled case, substantially of a cylindrical shape and made of metallic material. This case is closed at both the ends thereof by a pair of bottoms, an upper one and a lower one, substantially of a circular shape and also made of metallic material. This type of case is rather costly to manufacture and is subjected to air-seal problems next to the junction between case and bottoms, in addition to noise problems generated by vibrations between case and filtering pack. Object of the present invention is solving the above-mentioned prior art problems, providing an air filter for industrial vehicles equipped with polyurethane bottoms, that greatly reduce manufacturing costs, realize an air-sealing gasket next to their contact points with the case, and deaden noises due to vibrations between case and filtering pack. A further object of the present invention is providing a process for manufacturing such filter. The above and other objects and advantages of the invention, as will appear from the following description, are reached by an air filter for industrial vehicles as claimed in claim 1, and by a process for manuf cturing an air filter for industrial vehicles as claimed in claim 5. Embodiments of the air filter of the present invention are disclosed in claims 2 to 4, while variations of the process of the present invention are disclosed in claims 6 to 8. The present invention will be better described by some preferred embodiments thereof, provided as a non-limiting example, with reference to the enclosed drawings, in which: - Figure 1 is a side, partially sectional view of an embodiment of the air filter for industrial vehicles of the present invention; - Figure 2 is a top view of an embodiment of a lower bottom to be applied to the filter of the present invention; and - Figure 3 is a top view of an embodiment of an upper bottom to be applied to the filter of the present invention. With reference to the Figures, an air filter 1 for industrial vehicles essentially comprises a central, drilled support sleeve 3 around which a sheet 5 made of filtering material is disposed, said sheet 5 begin usually of a pleated shape and arranged as a circular crown around the sleeve 3. Sleeve 3 and filtering sheet 5 are inserted into a drilled case 7, substantially of a cylindrical shape, and then the case 7 is closed in the upper part thereof by an upper bottom 9 made of polyurethane. Joining between upper bottom 9 and case 7 is carried out by simply expanding the polyurethane, and this guarantees a perfect air seal, that was not possible before, when the upper metallic bottom and the metallic case were joined by glueing them. The upper bottom 9 of the present invention is of a circular shape and inside it an internal support member 11 is inserted or formed, said support member 11 also being of a circular shape and concentric with the upper bottom 9. Centrally to the internal support member 11 a through-hole is formed inside which common securing means, like screws and washers (not shown), are passed to secure the air filter to the engine. The internal support member 11 can be made of metallic material, or of polyurethane whose hardness is such as to allow securing the air filter to the engine: for example, if the upper bottom 9 is made of polyurethane whose hardness is Shore A, the internal support member 11 could be made of polyurethane whose hardness is Shore D. The case 7 is then closed also in the lower part thereof through a lower bottom 13, inside which a gasket is obtained and, in prior art, is glued. The lower bottom 13 is also of a circular shape and is preferably made of polyurethane, in order to guarantee the same air seal and the same cost-saving and noise-reduction features as the upper bottom 9. Also as regards the lower bottom 13, the securing thereof to the case 7 is carried out by simply expanding the polyurethane. Even if the lower bottom 13 is preferably made of polyurethane, it is possible to realize it also of metallic material and to join it to the case 7, in a known way, through glueing.. After having completed the air filter in such a way, it is inserted in an external vessel, usually of a cylindrical shape and made of hard plastic material, that is already arranged on the industrial vehicle engine in a known way. It clearly appears that, starting from the basic idea that consists in realizing at least one of the bottoms 9 and 13 in polyurethane, and in realizing the internal support member 11 of a hardness which is greater than the hardness of the upper bottom 9, it will be possible to create different types of embodiments of the air filter according to the invention, deriving from all possible combinations of the materials for bottoms 9 and 13 and support member 11. The process for manufacturing the air filter for industrial vehicles of the present invention will now be described. This process starts by assembling the sheet 5 made of filtering material around the support sleeve 3; the sheet 5 - sleeve 3 assembly is then inserted into the case 7, where assembling occurs by bearing. A polyurethane foaming or casting with open die is then carried out to create the upper bottom 9 and, in an embodiment of the process of the present invention, the internal support member 11, made of metallic material, is inserted centrally with respect to the upper bottom 9. Insertion of the case assembly 7 is then carried out in contact with the upper bottom 9, followed by the expansion of polyurethane composing the upper bottom 9 itself. After expansion, the upper bottom 9 will be joined both to the case 7, and to the internal support member 11 in order to create a perfect air seal. In the embodiment providing that the lower bottom 13 be also made of polyurethane, the case 7 is rotated and foaming or casting of the polyurethane in contact therewith is carried out, in order to create the lower bottom 13. Also here, after polyurethane expansion, a perfect air seal will be realized. In the embodiment providing the lower bottom 13 made of metallic material, a common glueing of the bottom 13 to the case 7 is carried out. Finally, in the embodiment providing that the internal support member 11 be also made of polyurethane whose hardness is greater than that of the polyurethane of which the upper bottom 9 is composed, a first foaming or casting of the hardest polyurethane is carried out and then a second foaming is carried out forming the upper bottom 9; these foamings and the following expansion of the two polyurethanes will generate the support member 11 and the sealing connection between member 11 and upper bottom 9.

Claims: CLAIMS 1. Air filter (1) for industrial vehicles comprising: - central support means (3) ; - air filtering means (5) arranged around said support means (3) ; - a case (7) arranged around said filtering means (5) ; and - an upper bottom (9) and a lower bottom (13) arranged in order to close said case (7) ; characterized in that: said upper bottom (9) is made of polyurethane; and - said upper bottom (9) includes inside thereto an internal support member (11) made of material whose hardness is greater that that of the material which said upper bottom (9) is made of. 2. Air filter (1) for industrial vehicles according to claim 1, characterized in that said lower bottom (13) is also made of polyurethane. 3. Air filter (1) for industrial vehicles according to claim 1 or 2, characterized in that said internal support member (11) is made of poluyrethane whose hardness is greater than the polyurethane which said upper bottom (9) is made of . 4. Air filter (1) for industrial vehicles according to claim 1 or 2, characterized in that said internal support member (11) is made of metallic material. 5. Process for manufacturing an air filter (1) for industrial vehicles comprising the steps of: - assembling air filtering means (5) around central support means (3) ; and - inserting said filtering means (5) inside a case (7) ; characterized in that it further comprises the steps of: - forming an upper bottom (9) through polyurethane foaming or casting; - inserting an internal support member (11) inside said upper bottom (9), the hardness of the material which said internal support member (11) is composed of being greater than that of the material which said upper bottom (9) is composed of; - arranging said case (7) in contact with said upper bottom (9) ; - expanding said upper bottom (9) to form a sealing junction with said case (7); and - completing said air filter (1) by connecting said case (7) and a lower bottom (13). 6. Process according to claim 5, characterized in that said completing step of said air filter (1) comprises the steps of: forming said lower bottom (13) through polyurethane foaming or casting; - arranging said case (7) in contact with said lower bottom (13) ; - expanding said lower bottom (13) to form a sealing junction with said case (7). 7. Process according to claim 5 or 6, characterized in that said inserting step of said internal support member (11) is carried out by foaming or casting a polyurethane whose hardness is greater than that of the polyurethane which the upper bottom (9) is made of. 8. Process according to claim 5 or 6 wherein said internal support member (11) is made of metallic material, characterized in that said inserting step of said internal support member (11) is carried out by disposing said internal support member (11) centrally with respect to said upper bottom (9) , the following expansion of said upper bottom (9) generating a seal between said upper bottom (9) and said internal support member (11).

Inventors: D ADDAZIO FRANCA, SURGO ALBERTO, D'ADDAZIO, FRANCA, SURGO, ALBERTO
Applicants: ADDAZIO FRANCA D, SURGO ALBERTO, TECNOCAR SRL, D'ADDAZIO, FRANCA, SURGO, ALBERTO
Application year: 1996
Main classification: B01D46
IPC codes: B01D46