GB1563649A

GB1563649A - Air filter casing

Info

Publication number: GB1563649A
Application number: GB2882277A
Authority: GB
Original assignee: Filterwerk Mann and Hummel GmbH
Current assignee: Mann and Hummel GmbH
Priority date: 1976-07-09
Filing date: 1977-07-08
Publication date: 1980-03-26

Description

(54) AN AIR FILTER CASING (71) We, FILTERWERK MANN & HUMMEL GMBH of Postbox No. 409, D 7140 Lugwigsburg, Federal Republic of Germany; a German body corporate do hereby declare the invention. for which we pray that a patent may be granted to us. and the method by which it is to be performed to be particularly described in and by the following statement: The present invention relates to an air filter casing for receiving a filter cartridge or to an air filter for internal combustion engines, compressors or other air inducing machines, including a two-part housing comprising a cup-shaped main housing part and a cover of resilient plastics material adapted to be secured to the edge of the main part by means of catch connections.

wherein the main housing part has a plurality of stop projections spread around its circumference and protruding radially outwards and wherein the enclosing portion of the cover has recesses adapted in number.

position and shape to co-operate with the stop projections.

In use, the stop connections have considerable physical demands made on them.

The catch-mounted cover has to be satisfactorily secured in order to resist stresses occurring during operation. This includes.

for example, bending stresses occurring during the clamping and sealing of a filter element and also includes superposed alternating stresses as may also result from pulsating effects of the induced air. Furthermore, it is desirable that the cover part should be readily engaged and released from the main housing part without the aid of any tool.

It is known from German Offenlegungsschrift No. 19 25 341 to provide an air filter with catch projections which are located on the outer periphery of a circular housing cover. The edge of the main housing part has a corresponding number of recesses adapted according to position and shape.

Such a notch closure may be released with the aid of a tool. The recesses in the edge of the main housing part may only be produced with complex tools. Moreover, the closure cover requires relatively precise tolerances to be maintained because of the nonresilience of the edge of the lower portion and manufacture costs are therebv further increased.

An air filter is disclosed in German Gebrauchsmuster No. 18 72 274 wherein the cover has stop projections projecting radial ly outwards from a cvlindrical jacket integrallv formed with the housing cover. Axially extending slots are formed in the outer surface of the cvlinder between the stop projections to obtain an improved radial resilience. This catch closure is so formed that it cannot be released without breaking the components. Furthermore, the recesses in the edge of the lower portion also require complex manufacturing tools.

Finally. housings of plastics material closeable bv cover catch closures are generallv known in which an annular stop bead is associated with an also annular stop groove.

The parts may be readily fitted together and disengaged from one another. The closure, however. is only able to resist extremelv slight disengagement forces because a correspondingly soft plastics material has to be used for the manufacturing capability and functional efficiencv of the stop closure.

It is an object of the invention to provide an improved connection between the parts of an air filter without the aid of additional components so that it also fulfills the conditions of strength required for rough operation and permits manual assembly and disengagement.

According to the present invention there is provided an air filter casing for internal combustion engines. compressors or other air inducing engines. including a two-part housing with a cup-shaped main housing part and a cover part made of resilient plastics material securable on a circular edge of the main housing part by means of catch connections, wherein the cover part has apertures adapted in number, position and shape to stop projections on the main part: wherein a plurality of stop projections are provided around the circumference of the edge of the main part, and project radially outwards; and wherein the cover part has an annular wall portion which when located on the main housing part overlaps the edge thereof and the annular wall portion has windows forming apertures therein each extending from the main portion of the cover body which lies substantially normal to the central axis of the cover part into the annular wall portion and forming abutments on the side remote from the main body of the cover part for co-operative engagement with said stop projections of the main housing part; said annular wall portion being provided with a plurality of outwardly projecting beads extending in a substantially axial direction and spread over the circumference of said wall portion and being located between the windows; said beads defining slots and therebv being adapted to flex to facilitate mounting and removal of the cover part.

The housing cover engaging over the edge of the lower and main housing part with a narrow annular rim is stable enough for a secure stop connection and because the beads extend in an axial direction such may be individuallv detached one after the other from the edge of the main part. Undercuts are completely avoided so that simple manufacturing tools may be used.

For simplifying manufacture in development of the invention. the annular wall portion and. in somewhat more pronounced manner, the beads on the cover bodv are inwardly inclined.

A feature of the invention which facilitates the manipulation of the cover portion whilst obtaining the smallest possible external dimensions. is characterised bv the feature that the annular wall portion is provided at its free end with an outwardlv directed edge and the beads are cut-off proceeding from a central regtion of the annular wall portion and extending to the outer circumference of said edge. Slots are thus formed which extend right into the central region of the annular wall portion and because thev are located in the bottom of the bead, have an upright collar which merges into the outwardly curved edge of the cover. Sufficient strength on the one hand and sufficient resilience on the other hand are ensured.

A satisfactorv seal of the closure in connection with a considerable insensibility to tolerance is provided in one embodiment of the invention wherein there is formed a concentric annular collar in the cover and within the annular wall portion which collar together with the annular wall portion forms an annular groove. Furthermore, the edge of the lower main housing part has an annular shoulder for receiving the end face of the annular collar when the housing cover is engaged thereon, whereby an axial spacing exists between the end face of the edge of the main part and the closed end of the annular groove.

In an alternative embodiment, the housing cover part has an annular collar formed within the annular wall portion and concentric therewith to form an annular groove with the annular wall portion. In this embodiment. the end of the annular groove has an axially projecting annular shoulder adjacent the annular collar and provided for engaging with the end face of the edge of the main housing part. the parts being shaped and dimensioned that the edge of the main housing part projects radially outwards beyond said annular shoulder.

When joining together housing cover and main housing part and also when disengaging the cover. the annular jacket has to be bent outwards and upwards in section. By the configuration in accordance with this embodiment of the invention, there is particularly attained, without the influence of manufacturing limits. a pivotal point about which the annular wall porton has to be bent up outwards. and which always assumes the same position, namely at the end face abutment of the edge of the main part with the annular shoulder.

The invention will be described further.

by way of example. with reference to the accompanying drawings. in which: Figul I is a schematic elevation of an air filter: Fi,Suie,7 is an enlarged plan view of a portion of the edge of the air filter of Figure 1: Figure 3 is a fragmentary side elevation of the edge of the main part of the housing with the housing cover positioned thereover: Figure 4 is a cross-section on an enlarged scale. through one form of connection and taken on the line 4 - 4 of Figure 2: Figure 5 is a section through the housing cover taken on line 5 - S of Figure 3; Figure 6 is a section on the line 6 - 6 of Figure 5: Figure 7 is an enlarged cross-section of a modification of the filter shown in Figures 1 to 3 and is taken through the connection region on the line 4 - 4 of Figure 2: Figlrre 8 is a section through the modification of filter taken on the lines 5 - 5 of Figure 3: and Figure 9 is a section of the modification corresponding to the section of Figure 6 of the first embodiment.

In Figures 1 to 6 an air filter 1 is shown including an induction pipe 2 which leads into a two-part housing 3 comprising a main, lower housing part 4 which is substantially cup-shaped, and a housing cover 7. Cover 7 is secured to the edge 5 of the lower portion 4 via a notch connection 6. A clean air pipe 8 leads from the lower part. The housing parts are made of resilient plastics material.

An annular interchangeable filter cartridge 9 is axially clamped and sealed, between the housing cover 7 and the bottom of the lower part 4.

In operation, induced air flows through the induction pipe into the housing 3, passes radially inwardly through the filter cartridge 9, leaves the air filter through the clean air pipe 8 and then passes to the air inducing engine (not shown).

The edge 5 of the main part 4 has several stop projections 11 spread around the circumference and projecting radially outwards and which are each supported by two lateral webs 12. The inside circumference of the edge of the lower part is provided with an annular shoulder 13.

The housing cover 7 comprises a cover body 21 located normal to the cover axis and body 21 merges. via a transitional region 29.

at its outer circumference into an annular jacket or wall 22. The annular wall 2' overlaps the edge 5 of the lower part and has apertures 24 forming windows and corresponding in number, position and shape to the projections 11. Each aperture 24 extends from one side from a transitional portion 25 of the cover body 21 through the annular jacket 22 to the opposite side which is adapted as an abutment 26 for a projection 11.

The annular wall 22 is provided with several outwardly projecting beads 31 spread along the circumference of the wal and located between the apertures 24. As shown in Figure 4 the annular wall 22 is inclined to the plane of the body 21 as are also, and to a somewhat greater extent. the beads 31. The expedient number of beads is to be ascertained bv trial. It mav. for example, prove favourable to provide a bead only after every second aperture.

The annular wall 22 has an outwardly inclined edge 32 at its free end. The beads 31 terminate at their exterior on an imagin- ary cylindrical surface running through the outer circumferences of the edges 32. This termination results in slots 28 which extend to the central region of the annular wall portion 22 and are enclosed by wall sections of the beads 31 in the manner of upright collars.

The housing cover 7 is provided with a concentric annular collar 35 within the annular jacket 22 which collar forms an annular groove 36 with the annular jacket 22. As is seen in Figure 4, when the cover 7 is in place, the annular collar 35 is supported by its face on the annular shoulder 13 of the edge 5 of the housing. The axial dimensions of the collar 35 and shoulder 13 are such that an axial spacing A is provided between the end face 5a of the edge 5 and end face 37 of the annular groove 36. The edge part of the housing cover 7 is hence not supported in this region and is thus able to yield and to therebv contribute towards bridging inevitable manufacturing tolerances.

In the modification shown in Figures 7 to 9. like reference numerals are given to like parts as in Figures 1 to 6.

In this embodiment. the housing cover 7 is provided with concentric annular collar 35 within annular wall portion 22 which collar together with the annular wall portion 22 extending from a transitional regional 29a forms annular groove 36.

The end 37 of the annular groove 36 has an axially protruding annular shoulder 38 adjacent to the annular collar 35. As shown in Figure 4. the edge 5 of the main housing part abuts with its end face 5a against the annular shoulder 38. The dimensions are such that the edge 5 of the main housing part 4 projects radially outwards beyond the annular shoulder 38. In this manner. should a burr possibly form at 39 on the end face 5a of the edge 5 of the main part 4 during manufacture by injection moulding it is ensured that the burr does not abut against the housing cover 7.

WHAT WE CLAIM IS: l. An air filter casing for internal combustion engines, compressors or other air inducing engines, including a two-part housing with a cup-shaped main housing part and a cover part made of resilient plastics material securable on a circular edge of the main housing part by means of catch connections: wherein the cover part has apertures adapted in number. position and shape to stop projections on the main part: wherein a plurality of stop projections are provided around the circumference of the edge of the main part. and project radially outwards: and wherein the cover part has an annular wall portion which when located on the main housing part overlaps the edge thereof and the annular wall portion has windows forming apertures therein each extending from the main body of the cover part which lies substantially normal to the central axis of the cover part into the annular wall portion and forming abutments on the side remote from the main body of the cover part for cooperative engagement with said stop projections of the main housing part: said annular wall portion

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

Figure 9 is a section of the modification corresponding to the section of Figure 6 of the first embodiment.

In Figures 1 to 6 an air filter 1 is shown including an induction pipe 2 which leads into a two-part housing 3 comprising a main, lower housing part 4 which is substantially cup-shaped, and a housing cover 7. Cover 7 is secured to the edge 5 of the lower portion 4 via a notch connection 6. A clean air pipe 8 leads from the lower part. The housing parts are made of resilient plastics material.

An annular interchangeable filter cartridge 9 is axially clamped and sealed, between the housing cover 7 and the bottom of the lower part 4.

In operation, induced air flows through the induction pipe into the housing 3, passes radially inwardly through the filter cartridge 9, leaves the air filter through the clean air pipe 8 and then passes to the air inducing engine (not shown).

The edge 5 of the main part 4 has several stop projections 11 spread around the circumference and projecting radially outwards and which are each supported by two lateral webs 12. The inside circumference of the edge of the lower part is provided with an annular shoulder 13.

The housing cover 7 comprises a cover body 21 located normal to the cover axis and body 21 merges. via a transitional region 29.

at its outer circumference into an annular jacket or wall 22. The annular wall 2' overlaps the edge 5 of the lower part and has apertures 24 forming windows and corresponding in number, position and shape to the projections 11. Each aperture 24 extends from one side from a transitional portion 25 of the cover body 21 through the annular jacket 22 to the opposite side which is adapted as an abutment 26 for a projection 11.

The annular wall 22 is provided with several outwardly projecting beads 31 spread along the circumference of the wal and located between the apertures 24. As shown in Figure 4 the annular wall 22 is inclined to the plane of the body 21 as are also, and to a somewhat greater extent. the beads 31. The expedient number of beads is to be ascertained bv trial. It mav. for example, prove favourable to provide a bead only after every second aperture.

The annular wall 22 has an outwardly inclined edge 32 at its free end. The beads 31 terminate at their exterior on an imagin- ary cylindrical surface running through the outer circumferences of the edges 32. This termination results in slots 28 which extend to the central region of the annular wall portion 22 and are enclosed by wall sections of the beads 31 in the manner of upright collars.

The housing cover 7 is provided with a concentric annular collar 35 within the annular jacket 22 which collar forms an annular groove 36 with the annular jacket 22. As is seen in Figure 4, when the cover 7 is in place, the annular collar 35 is supported by its face on the annular shoulder 13 of the edge 5 of the housing. The axial dimensions of the collar 35 and shoulder 13 are such that an axial spacing A is provided between the end face 5a of the edge 5 and end face 37 of the annular groove 36. The edge part of the housing cover 7 is hence not supported in this region and is thus able to yield and to therebv contribute towards bridging inevitable manufacturing tolerances.

In the modification shown in Figures 7 to 9. like reference numerals are given to like parts as in Figures 1 to 6.

In this embodiment. the housing cover 7 is provided with concentric annular collar 35 within annular wall portion 22 which collar together with the annular wall portion 22 extending from a transitional regional 29a forms annular groove 36.

The end 37 of the annular groove 36 has an axially protruding annular shoulder 38 adjacent to the annular collar 35. As shown in Figure 4. the edge 5 of the main housing part abuts with its end face 5a against the annular shoulder 38. The dimensions are such that the edge 5 of the main housing part 4 projects radially outwards beyond the annular shoulder 38. In this manner. should a burr possibly form at 39 on the end face 5a of the edge 5 of the main part 4 during manufacture by injection moulding it is ensured that the burr does not abut against the housing cover 7.

WHAT WE CLAIM IS: l. An air filter casing for internal combustion engines, compressors or other air inducing engines, including a two-part housing with a cup-shaped main housing part and a cover part made of resilient plastics material securable on a circular edge of the main housing part by means of catch connections: wherein the cover part has apertures adapted in number. position and shape to stop projections on the main part: wherein a plurality of stop projections are provided around the circumference of the edge of the main part. and project radially outwards: and wherein the cover part has an annular wall portion which when located on the main housing part overlaps the edge thereof and the annular wall portion has windows forming apertures therein each extending from the main body of the cover part which lies substantially normal to the central axis of the cover part into the annular wall portion and forming abutments on the side remote from the main body of the cover part for cooperative engagement with said stop projections of the main housing part: said annular wall portion

being provided with a plurality of outwardly projecting beads extending in a substantially axial direction and spread over the circumference of said wall portion and being located between the windows; said beads defining slots and thereby being adapted to flex to facilitate mounting and removal of the cover part.
2. An air filter casing as claimed in claim 1, in which the annular wall portion is upwardly inwardly inclined as are the beads on the cover body to a greater extent.
3. An air filter casing as claimed in claim 1, in which the annular wall portion is provided with an outwardly set edge at its free end and in which the beads proceeding from the central cover region are cut off tapering towards the outer circumference of the edge.
4. An air filter casing as claimed in any of claims 1 to 3, in which the housing cover has an annular collar within the annular wall portion and concentric therewith with said collar forming an annular groove with the annular wall portion, and in which the edge of the main housing part has an annular shoulder for supportingly receiving the end face of the annular collar when the housing cover is secured thereon, whereby the parts are dimensioned such that when secured together an axial spacing (A) exists betwen the upper end face of the edge of the lower part and the end face of the annular groove.
5. An air filter casing as claimed in any of claims 1 to 3, in which the housing cover part has an annular collar formed concentrically and within the annular wall portion and which forms an annular groove with the annular wall portion, in which the end of the annular groove has an axially projecting annular shoulder adjacent to the annular collar and for engaging with the end face of the edge of the main housing part and in which the edge of the main housing projects radially outwards beyond said annular shoulder.
6. An air filter casing substantially as herein described with reference to and as illustrated in Figures 1 to 6 or Figures 1 to 3 and Figures 7 to 9 of the accompanying drawings.