METHOD FOR MAKING A CURVED, CORRUGATED ARTICLE AND APPARATUS THEREFOR

Abstract: A method and apparatus for making axial-flow filter wherein a curved corrugation is made from a flat sheet of filter material in the first step, and thereafter the curved corrugation is made circular to obtain the final product intended. In the first step, the flat sheet (2) of filter material is attached to a mold (3) so that it is slanted up from one end thereof, thereafter a set of fixing blades (4) is moved down to the mold to fold the flat sheet of filter material conse­ cutively into a curved corrugation. In the second step the curved corrugation thus produced is made circular by using a contouring belt which embraces the outer circumference of the curved corrugation.

Description: METHOD FOR MAKING AXIAL-FLOW FILTER AND APPARATUS THEREFOR BACKGROUND OF THE INVENTION The present invention relates to a filter, particularly an axial-flow filter that is useful to filtrate foreign matters in the air or oil. The axial-flow filter of the present invention is compact and light weight, therefore useful in various kinds of vehicles. The subject of the present invention is in the method to mass produce the axialflow filter and the apparatus to make those filters. Conventionally, the axial-flow filter is made in a very primitive way, i.e. they used a flexible base sheet made of many corrugations, and they applied a flat sheet of filter material onto the base sheet, and then folded the filter material along the corrugations of the base sheet to finally obtain a corrugated sheet of filter material. The method is as readily understood very unstable and time consuming. Therefore it took for example two minutes to obtain the corrugated filter material which is about 300 mm in diameter, which shows very low productivity. Especially it was impossible to uniformly fold the corrugations since it relys on hand work of workers in the line. Therefore the filtration#performance varies from one another and the appearence of the resultant filter is poor, thus reducing the value of the merchandise. Besides the method above explained, we are not informed of any other method to produce the axial-flow filter in detail. It is conceivable that the automated process to make the filter is difficult, since it has to deal with soft or flexible material of filter material which is different from rigid and solid material like metal or hard plastic. SUMMARY OF THE INVENTION The present invention purposes to obtain a practical and fast way to produce the axial-flow filter and the apparatus therefor. In the present invention, the axial-flow filter is made between a mold located under the filter material provided and a set of fixing blades which is moved to the mold to fold the filter material to obtain the curved corrugation of the filter material. In the process, the filter material is corrugated with a certain curvature in a moment. This process would be useful in corrugating other materials than filter material such as fin metallic material or plastic material. Another purpose of the present invention is to make the curved corrugation obtained above circular in a succeeding process where the curved ' corrugation is forced circumferentially to get the two ends together to make as a whole a round axial-flow filter. This process is accomplished in a machinery developed by us at a high speed. The above two processes may be combined together to make the curved corrugation first and after that the rounding process is combined, thus making a continuous line to make the axial-flow filter from a flat sheet of filter material to the round end product of the axial-flow filter. The other objects, features, and advantages of the present invention would become apparent from the following description and drawings of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view of a fan-shaped flat sheet of filter material, Fig. 2 is a perspective view where the flat sheet of Fig. 1 is attached to a mold to produce a curved corrugation, Fig. 3 shows a perspective view of the flat sheet corrugated on the mold, Fig. 4 is a perspective view where the curved corrugation is placed on a center rod around which the curved corrugation is made round, Fig. 5 shows a perspective view of the final product of the axial-flow filter, Fig. 6 shows a partial-crosssectional side view of the apparatus to make the curved corrugation from the flat sheet, Fig. 7 shows a front view of a set of fixing blades which come down to the mold to fold the flat sheet consecutively, Fig. 8 shows a cross-sectional view of the mold of a modified consstruction, Fig. 9 shows a partial-crosssectional front view of the apparatus to make the curved corrugation circular, Fig. 10 shows a bottom view of the apparatus shown in Fig. 9, Fig. 11 shows a plane view of a reshaper mounted in the apparatus of Fig. 9, Fig. 12 shows the curved corrugation made circular in the apparatus of Fig. 9 at its initial condition, and Fig. 13 shows a partial-crosssectional front view of another modification of the apparatus shown in Fig. 9. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Fig. 1 shows a flat sheet of filter material 2 which is cut to be a fan-shaped configuration. The flat sheet has two curved edges 2b and two tapered side edges 2c, and also a set of curved depressions which has the same curvature as the curved edges 2b on one side of the flat sheet of filter material 2. In Fig. 2, numeral 3 designates a mold which has a curved wavy surface 3a on one side thereof. The curved wavy surface 3a is made of valleys which have bottom edges and ridges which have top edges. The curved wavy surface 3a with the varies and ridges is curved in a certain radius. The mold 3 also has a curved end 3b at the inner end thereof. The flat sheet of filter material 2 is fixed at the curved end 3b as shown in the figure, thus the flat sheet of filter material 2 is curved and raised from the curved wavy surface 3a like a part of a conical surface. On the flat sheet of filter material 2 thus slanded a set of fixing blades 4a, 4b and 4c is positioned. After that the set of fixing blades 4a, 4b and 4c is moved downward to fold the flat sheet of the filter material 2 along the upper face of the curved wavy surface 3a as shown in Fig. 3 to obtain a curved corrugation 2c. The curved corrugation 2c thus produced is positioned on a center rod 5 to round the curved corrugation 2c afterwards along the dotted line A as shown in Fig. 4. When all the steps from Fig. 1 to Fig. 4 are worked out, and when the round curved corrugation obtained in Fig. 4 is reshaped, the final product of the axial-flow filter 21 is obtained as shown in Fig. 5. The steps of Figs. 2 and 3 are explained in detail in association with Figs. .6 and 7. The mold 3 has curved ridges 3f, 3g, 3h, 3i and 3j. The flat sheet of filter material 2 is fixed to the mold 3 at the curved end 3b by a clamper 14 to raise the flat sheet 2 as shown in Fig. 6. When the clamper 14 is located as shown in Fig. 6, the set of fixing blades 4a to 4e is positioned as shown in Fig. 6, i.e. each of the fixing blades is located close to the surface of the flat sheet 2. The clamper 14 is moved by an air cylinder 13 and fixing blades 4a to 4e are moved by air cylinders 8a, 8b, 8c, 8d and 8e. All the air cylinders 4a to 4e are fixed to a plate 7, therefore when the plate 7 is moved downward in Fig. 6, all the air cylinders 8a to 8e start to move down simultaneously. When the plate 7 is moved downward, the fixing blade 4a first folds the flat sheet 2 in such a manner that the blade 4a mates with the valley of the mold 3 between the ridges 3f and 3g. At that time the next fixing blade 4b is located on the flat sheet 2 to fold the next corrugation in a second. Likewise the succeeding blades 4c, 4d and 4e are moved downward to make the following corrugations on the mold 3. During the downward movement of the plate 7, i.e the whole cylinders 8a to 8e, the stems of the fixing blades are inserted into the respective air cylinders. Since the initial positions of the fixing blades 4a to 4e are differentiated stepwise, a single downward movement on the plate 7 folds the flat sheet 2 consecutively at a high speed to obtain a curved corrugation 2c on the mold 3. The plate 7 is supported and guided by guide columns 12 and moved by an oil cylinder 10 fixed to an upper beam 11. All these things are made on the base 6. Numeral 51 designates a heater that is located between the neighboring fixing blades. The heater 51 heats up the curved corrugation 2c on the top edges of the curved ridges 3f to 3j to deform the sheet 2 permanently at those portions, when all the fixing blades 4a to 4e are moved down completely. The mold 3 may include a heater to heat up the curved corrugation 2c made on the curved wavy surface 3a. With the aid of the heater 51 and the heater to be mounted in the mold 3, the curved corrugation made on the mold 3 may be regidified to keep the shape of the curved corrugation made on the mold 3. Although air cylinders are utilized for the stems of the fixing blades 4a to 4e, it is possible to replace the air cylinders wit simple springs to absorve the movement of the stems and afterwards extend those stems again. The relationship among the fixing blades 4a, 4bt 4c, 4d and 4e, flat sheet of filter material 2 and the mold 3 is as shown in Fig. 7. As is apparent from this figure, the flat sheet 2 is slanted upward from the inner end thereof and also makes a conical plane above the mold 3. The locations of the fixing blades 4a to 4e are indicated therein, i.e. each fixing blade is positioned just above the inclined conical plane of the flat sheet of the filter material 2. Each of the fixing blades 4a to 4e is also curved as the ridges 3f to 3j of the mold 3, since each blade must mate with each valley of the curved wavy surface of the mold 3. The edges of the fixing blades 4a to 4e are sharpened as indicated in this figure. Also, each blade becomes wider in lateral width as the width of the flat sheet 2 becomes wider. In Figs. 6 and 7, the curved wavy surface of the mold 3 is made plane, i.e. the general lateral line of the ridges 3f to 3j is in parallel with the surface of the base 6, however it is possible to incline the general lateral line in respect of the surface of the base 6. If done so, the resultant curved corrugation on the mold 3 would have a general lateral inclined line with respect to the base 6. To obtain the inclined curved corrugation, the curved wavy surface of the mold 3 should be modified a little, i.e. the upward slope of the ridge 3f must be made longer than the downward slope of the ridge 3f, the upward slope of the ridge 3g must be longer than the downward slope of the ridge 3f, and again the downward slope of the ridge 3g must be shorter than the upward slope of the ridge 3g. If these arrangements are made on the curved wavy surface of the mold 3, it is possible to obtain an inclined curved corrugation on the mold 3. In practical use for example in automobiles, an inclined curved corrugation, i.e. a slightly conical axial-flow filter made by rounding the inclined curved corrugation is better mounted in an air cleaner thereof since the inclined general line of the axial-flow filter produces a space through which the air can communicate with the intake system of the engine. Fig. 8 shows another embodiment of the mold 3 where the mold 3 is divided into two parts, i.e. top mold 31 and base mold 32. The top mold 31 functions to form the top edges of the ridges 3f to 3j to enable-to obtain various types of curved corrugations whose heights are different from each other. For example if the top mold 31 is raised a little from the base mold 32, the flat sheet of filter material 2 is folded deeply to obtain a larger height in the curved corrugation to be obtained thereon. By using this modified mold, it is possible to obtain various types of axial-flow filters in the same apparatus over all. Even if the height of the folding is differentiated from each other, the curved corrugation of any height can be obtained since the pitch of the corrugation or the pitch of the fixing blades 4a to 4e does not change at all. An embodiment of the flat sheet filter material 2 is a three-ply filter material which has a coarse or low density material on top, a middle density material next, and at the bottom a high density material. This kind of filter material is useful, if it is used to pass the air from the coarse size to the high density side since the coarse material filtrates relatively larger foreign materials first and then the last one filtrates any unpermissible foreign materials. When this kind of filter material is used in the apparatus explained above, the coarse side of the material should be faced with the fixing blades 4a to 4e. If the material is so placed in the apparatus, the curved corrugation obtained would have the coarse side on top of the same and the high density side on the bottom side thereof. When the curved corrugation is made conical as explained above as another embodiment, the coarse side is the outer surface of the corn and the high density side is the inner side of the corn. The process and apparatus to make the curved corrugation circular are explained with reference to Figs. 9 and 10. In Fig. 9, the curved corrugation previouslly made is put on a desk 23, and located in contact with the center rod 52. Numeral 5 designates a contouring belt which is curved at its initial position as shown in Fig. 10. The contouring belt 5 is made of a spring material and flexible, therefore it flexes when the ends of the contouring belt 5 is moved toward the center rod 52. The contouring belt 5 is so located that it can embrace the circumference of the curved corrugation. Numeral 6 designates a contouring belt holder to hold respective end of the contouring belt 5. The countering belt holder 6 has a cam follower 7 on top thereof and made slideable on the guide bar 8. The both ends of the guide bar 8 are supported by guide bar holders 9a and 9b which have cam followers 16 and 9b. Numeral 11 designates a cam plate fixed to the base plate 22. The cam plate 11 has three cam grooves 12a, 12c and 12b. Each of the cam grooves 12a, 12c and 12b receives each of the cam followers 10a, 7 and lOb. The lever 13 is rotated around a pin 14 and has a long hole 15 therein into which the cam follower 16 is engaged. The lever 13 is rotated by a gear 17 which is rotated by another gear 21 fixed to an output shaft of an air cylinder 20 which works to rotate the gear 21. Numeral 18 designates a tension coil which exert a tensile forth to the cam follower 10b. The arrangement as the above is duplicated on the other side of the apparatus in Fig. 9 as confirmed in Fig. 10. To the stands 24 are there fixed base plate 22 and the desk 23. When the air cylinder 20 is energized to rotate the gears 21 and 17, the lever 13 is rotated counter-clockwise in Fig. 10. At that time the cam follower 16 is pushed by the inner surface of the long hold 15 in the lever 13, therefore the guide bar holder 9a moves counter-clockwise to follow the path 22a which is made through the base plate 22 as shown in Fig. 10. On the other hand the holder 9b is pulled by the tension coil 18 toward the rotational center of the lever 13. When the lever 13 is rotated as the above, the cam follower 10b also rotates along the cam groove 12b. Since the cam follower 16 is guided by the long hole 15 and since the holder 9b is pulled toward the rotational center of the lever 13 and also since the length of the guide bar 8 is fixed, the position and the direction of the guide bar 8 is determinative of the rotational angle of the lever 13. Therefore the position and the direction of the cam follower 7 or fixing blade holder 6 are also determined according to the rotational angle of the lever 13. When the fixing blade holder 6 is moved along the cam groove 12c to the final position shown in dotted line in Fig. 10, the ends of the curved corrugation meet together to make a round axial-flow filter with reduced diameter. As shown in Fig. 10 when the guide bar 8 comes to a vertical position as shown in dotted line, the process of. rounding the curved corrugation is finished. The above arrangements of cam followers and cam grooves are made in such a way that the both ends of the countering belt 5 trace a line where the curved corrugation 2c is made smaller and simultaneously made circular. In Fig. 9, numeral 29 designates an aperture made through the base plate 22. A pusher 26 is pushed down through the aperture 29 by the operation of the air cylinder 28 which is supported by a stay 27 fixed to the base plate 22. The curved corrugation made circular below the pusher 26 is pushed down to the reshaper 30. The reshaper 30 is composed of two devided rotors 32 on which semi-circular teeth 33 are provided. The rotors 32 are rotated by pins 37 which are engaged with long holes 36 made at the ends of the rotors 32. When the air cylinder 38 is actuated, the pins 37 are rotated through gears 35. The semi-circular teeth on the rotors 32 are initially positioned as shown in Fig. 11. However, when the air cylinder 38 is actuated, the teeth 33 or the rotors 32 rotate toward each other, so that the triangular blank shown in Fig. 11 is filled with the semi-circular teeth 33. At this time, the upper or the other ends of the semi-circular teeth 33 are positioned as indicated by dotted line in Fig. 11. When the rounded curved corrugation is pushed into the reshaper 30, the grooves thereof mate with the semi-circular teeth at their initial positions, registering the center hole of the round curved corrugation at the center guide pin 31. At this time the ends of the rounded curved corrugation are not circular enough as shown in Fig. 12, however when the rotors 32 or semi-circular teeth 33 are rotated as shown in arrows in Fig. 11, the still straight ends of the rounded curved corrugation are made circular along the circular teeth 33 of the reshaper 30. After the reshaping operation by the reshaper 30 is finished, the reshaper 30 with the reshaped round curved corrugation is pulled out by the operation of the slide plate 39, so that it could be placed on the following step. Another embodiment of making the curved corrugation circular is explained with reference to Fig. 13. In this embodiment, there are three countering belts. In addition to the countering belt holder 6 shown in Fig. 9, are there provided two more countering belt holders 6b and 6c. As to the additional countering belt holders 6b and 6c, there are provided corresponding cam followers 7b and 7c which engage with corresponding cam grooves 12cb and 12cc. Since this apparatus has two more countering belts 5b and 5c in addition to the belt 5 shown in Fig. 9, they can grasp more valleys of the curved corrugation 2c. This construction is especially suitable when a number of valleys or ridges are made in one curved corrugation. The number of countering belts of course depends on the particular curved corrugation or axial-flow filter desired. It has been found that five countering belts are suitable when one makes an axial-flow filter with nine ridges or valleys. In the arrangement of Fig. 13 the pusher 26 must avoid a plurality of countering belts 5, 5b and 5c, therefore it has tso slits therein to successfully push down the rounded curved corrugation made therebelow. As explained above the method and apparatus of the present invention to make axial-flow filters are suitable to massproduce the filters fast with stability. Especially it is possible to produce various kinds of axial-flow filters whose heights are different from each other and where the number of valleys or ridges differ from each other in a single apparatus. The method disclosed is for making a curved corrugation from a flat sheet of material, including the steps of preparing the flat sheet of material, preparing a mold having a curved wavy surface at one side thereof, fixing an end of the flat sheet to a curved end of the mold so that the flat sheet is curved an inclined with respect to the curved wavy surface of the mold, preparing a set of fixing blades each of which mates with each of the bottom edges of the curved wavy surface when moved to the wavy surface, moving the set of blades toward the wavy surface, and folding the fixed flat sheet continuously along said curved wavy surface to make said curved corrugation in such a manner that the blade closest to the fixed end of the flat sheet is moved first and thereafter the successive blades are moved consecutively. In otherwords, it is said that a method is disclosed for making an axial-flow filter comprising the steps of preparing a flat sheet of filter material, preparing a mold having a curved wavy surface at one side thereof, fixing an end of the flat sheet to a curved end of the mold so that the flat sheet is curved and inclined with respect to the curved wavy surface of the mold, preparing a set of fixing blades each of which mates with each of the bottom edges of the curved wavy surface when moved to the wavy surface, and moving said set of blades toward the wavy surface, folding said fixed flat sheet continuously along said curved wavy surface to make a curve corrugation in such a manner that a blade closest to said fixed end of the flat sheet is moved first and thereafter the successive blades are moved consecutively, positioning a center rod close to an inner curved end of said curved corrugation, positioning a contouring belt over an outer curved circumference of the curved corrugation, and moving said contouring belt toward the center rod in such a manner that the helt#makes a circle around said center rod, said curved corrugation being made circular between the belt and center rod. Further an apparatus is disclosed for making an axial-flow filter from a flat sheet of material comprising a mold having a wavy curved surface on one side thereof which corresponds to a curved corrugation from which the axial-flow filter is made, said mold having a sloped and curved inner end, a means for fixing an end of said flat sheet with said sloped and curved inner end in such a manner that the flat sheet is curved along the inner end and slanted up continuously, a set of fixing blades located apart from the curved and slanted flat sheet, a means for moving a fixing blade closest to said end fixing means and moving remaining fixing blades consecutively from the one closer to said end fixing means to the one farthest from said end fixing means toward the wavy curved surface, so that said curved corrugation is made between the wavy curved surface and the fixing blades, a center rod located close to an inner end of the curved corrugation, a contouring belt located around an outer end of the curved corrugation for embracing the same, a means for grasping each ends of the contouring belt, a means for moving the grasping means along a predetermined puth so that the contouring belt makes a circle round the center rod with the curved corrugation made circular therebetween.

Claims: What we claim is: 1. A method for making a curved corrugation from a flat sheet of material comprising the steps of: preparing said flat sheet of material, preparing a mold having a curved wavy surface at one side thereof, fixing an end of said flat sheet to a curved end of said mold so that said flat sheet is curved and incline & with respect to said curved wavy surface of said mold, preparing a'set of fixing blades each of which mates with each of the bottom edges of said curved wavy surface when moved to said wavy surface, and moving said set of blades toward said wavy surface, folding said fixed flat sheet continuously along said curved wavy surface to make said curved corrugation in such a manner that a blade closest to said fixed end of said flat sheet is moved first and thereafter the successive blades are moved consecutively. 2. A method for making a curved corrugation from a flat sheet of material as claimed in claim-l, further comprising the step of: pressing the curved top edges of said curved corrugation by a heater after said curved corrugation is made between said fixing blades and said wavy surface for rigidifying said curved corrugation. 3. A method for making a curved corrugation from a flat sheet of material as claimed in claim 1 or 2, further comprising the step of: heating said mold for fixing the shape of said curved corrugation made between said fixing blades and said wavy surface. 4. A method for making a curved corrugation from a flat sheet of material as claimed in claim 3, wherein: said flat sheet of material is fan-shaped with two curved edges and two 'tapered side edges, and made of filter material, one of said two curved edges being fixed to said mold. 5. A method for making an axial-flow filter comprising the steps of: preparing a flat sheet of filter material, preparing a mold having a curved wavy surface at one side thereof, fixing an end of said flat sheet to a curved end of said mold so that said flat sheet is curved and inclined with respect to said curved wavy surface of said mold, preparing a set of fixing blades each of which mates with each of the bottom edges of said curved wavy surface when moved to said wavy surface, moving said set of blades toward said wavy surface, folding said fixed flat sheet continuously along said curved wavy surface to make a curved corrugation in such a manner that a blade closest to said fixed end of said flat sheet is moved first and thereafter the successive blades are moved consecutively, positioning a center rod close to an inner curved end of said curved corrugation, positioning a contouring belt over an outer curved end of said curved corrugation, and moving said contouring belt toward said center rod in such a manner that said belt makes a circle around said center rod, said curved corrugation being made circular between said belt and said center rod. 6. A method for making an axial-flow filter as claimed in claim 5 further comprising the step of: locating a reshaper having circular teeth which mate with valleys of said circular-made curved corrugation at a disconnected portion of said circular-made curved corrugation for reshaping the ends of said circular-made corrugation. 7. An apparatus for making a curved corrugation from a flat sheet of material comprising: a mold having a wavy curved surface on one side thereof which corresponds to said curved corrugation in shape, said mold having a sloped and curved inner end, a moans for fixing an end of said flat sheet with said sloped and curved inner end in such a manner that said flat sheet is curved along said inner end and slanted up continuously, a set of fixing blades located apart from said curved and slanted flat sheet, and a means for moving a fixing blade closest to said end fixing means and moving remaining fixing blades consecutively from the one closer to said end fixing means to the one farthest from said end fixing means toward said wavy curved surface, so that said curved corrugation is made between said wavy curved surface and said fixing blades. 8. An apparatus for making a curved corrugation from a flat sheet of material as claimed in claim 7, wherein: said set of fixing blades is so located as that each blades are consecutively raised from the one closest to said end fixing means to the one farthest from said end fixing means, and said set of fixing blades is moved all together toward said wavy curved surface so that each of said fixing blades is consecutively pressed down to each of a bottom edge of a valley of said wavy curved surface. 9. An apparatus for making a curved corrugation from a flat sheet of material as claimed in claim 8 further comprising: a set of heaters located between said fixing blades respectively for pressing top edges of said curved corrugation formed between said wavy curved surface and said fixing blades, and another set of heaters placed in association with said mold for heating the same. 10. An apparatus for making an axial-flow filter from a flat sheet of material comprising: a mold having a wavy curved surface on one side thereof which corresponds to a curved corrugation from which said axial-flow filter is made, said mold having a sloped and curved inner end, a means for fixing an end of said flat sheet with said sloped and curved inner end in such a manner that said flat sheet is curved along said inner end and slanted up continuously, a set of fixing blades located apart from said curved and slanted flat sheet, a means for moving a fixing blade closest to said end fixing means and moving remaining fixing blades consecutively from the one closer to said end fixing means to the one farthest from said end fixing means toward said wavy curved surface, so that said curved corrugation is made between said wavy curved surface and said fixing blades, a center rod located close to an inner end of said curved corrugation, a contouring belt located around an outer end of said curved corrugation for embracing the same, a means for grasping each ends of said contouring belt, and a means for moving said grasping means along a predetermined path so that said contouring belt makes a circle around said center rod with said curved corrugation made circular therebetween. 11. An apparatus for making an axial-flow filter from a flat sheet of material as claimed in claim 10 further comprising: a supporting belt located inside of said contouring belt to mate with a valley of said curved corrugation for bending said curved corrugation together with said contouring belt to a circular axial-flow filter. 12. An apparatus for making an axial-flow filter from a flat sheet of material as claimed in claim 10 or 11 further comprising: a reshaper having semi-circular teeth therein for receiving said curved corrugation made circular, mating respective valleys of said curved corrugation made circular and said teeth in order that the ends of said curved corrugation made circular are reshaped by said semi-circular teeth.

Inventors: ITO, YUUJI, KONDO, NAOHIKO, MATUYAMA, HARUKAZU, OTA, YUKIO, SAKAI, MASAHIKO, SHIBATA, TADAHIKO
Applicants: NIPPONDENSO CO., LTD.
Application year: 1985
Main classification: B01D29
IPC codes: B01D46, B31F1, B31D5, B01D29