Level probe/fuel feed pump combination in particular for a motor vehicle tank

Abstract

 To obviate the drawbacks both of in-tank fuel feed pumps associated with the fuel level indicator probe and of those installed along the feed line but without renouncing the advantages of both systems, the invention provides a fuel feed pump (4) of the type associated with the level probe (3), which is mounted elastically within a pocket (6) sealed against the tank interior by an elastic cowl (18).

Description

[0001] This invention relates to a level probe/fuel feed pump combination in particular for a motor vehicle tank.

[0002] Fuel feed pumps are required to overcome the head present between the tank and the engine.

[0003] Pumps structured to be installed along the fuel pipe are known.

[0004] These pumps are tendentially costly as they have to be individually fitted into a specific housing and require the fuel pipe to be interrupted, this being a possible cause of subsequent leakage.

[0005] To reduce costs, feed pumps integral with the fuel level indicator probe have been conceived in order to form a monolithic unit which can be quickly fixed to the tank upper wall so that the pump lies within the tank.

[0006] However because of the particular position of the pump such units suffer from safety problems especially with regard to any explosion which could occur following the slackening (including accidental slackening) of electrical connections.

[0007] The object of the present invention is to obviate the aforesaid drawbacks by providing a level probe/fuel feed pump combination which is safe against explosion as is a pump housable along the pipe, while at the same time being simple and economical to install as it forms part of a combination which also comprises the level probe.

[0008] These objects are attained by a level probe/fuel feed pump combination in particular for a motor vehicle tank, in accordance with claims 1 and 6.

[0009] In this combination the fuel feed pump is housed together with the level probe using the available space of the tank, and dips directly into the tank. The pump however remains outside said tank and poses no safety problems.

[0010] The pump is illustrated by way of non-limiting example in the figures of the accompanying drawings.

Figure 1 is a section through a first embodiment of a level probe/fuel feed pump combination according to the invention;

Figure 2 shows an enlarged detail of the combination of Figure 1;

Figure 3 is a section through a second embodiment of a level probe/fuel feed pump combination according to the invention;

Figure 4 is a top plan view of the second embodiment of the level probe/fuel feed pump combination;

Figure 5 is a view to an enlarged scale showing how the upper part of the pump of the second embodiment is fixed;

Figure 6 is a view to an enlarged scale showing the gasket which aids the fixing of the lower part of the pump of the second embodiment.

[0011] With reference to the aforesaid figures and in particular to Figures 1 and 2, the level probe/fuel feed pump combination of the invention, defined hereinafter simply as the combination and indicated overall by 1, comprises substantially a flange 2, a level probe 3 and a feed pump 4.

[0012] The flange 2, which is usually of circular plan, comprises through holes 5 in its edge for fixing it by screws (not shown) to the outside edge of an aperture provided in the upper wall of the tank, not shown. On that side which is to face the tank interior, the flange 2 supports the level probe 3, which is therefore located within the tank. The level probe 3 is of known type and is therefore not described. It is preferably of the type described in Italian patent application 68525 A/81.

[0013] On that side of the flange 2 which is to face the tank interior there is provided a pocket 6 in which the fuel feed pump 4 is elastically mounted. Said pump dips into the tank at the base 7 of said pocket 6. A hydraulic seal between the pump 4 and the base 7 of the pocket 6 is achieved at said point by interposing between said two elements an elastic cowl 18 fixed by hose clamps 8 at its larger diameter edge 17 to the pocket 6 and fixed at its smaller diameter edge 23 to the pump 4.

[0014] Preferably the pocket 6 has a shape obtained by joining together along an axis 10 three aligned tubular elements 9, 10, 11 having diameters which progressively decrease towards the base 7. The diameter difference between the first tubular element 9 and the second 10 results in a first projection 13, which acts as a support for an elastic element 14 supporting the pump 4. The elastic support element 14 for the pump 4 has an "L" cross-section, is fixed to the pump 4 by a hose clamp 15 and rests on the first projection 13. The diameter difference between the second tubular element 10 and the third 11 results in a second projection 16, to which the larger diameter edge 17 of the elastic cowl 18 is fixed, its smaller diameter edge 23 being fixed to the suction pipe stub 19 of the pump 4. The elastic cowl is of double "U" cross-section. On the pipe stub 19 there is mounted a tubular element 20 with which there is associated a filter 21 of the type which deforms elastically by the effect of the variation in distance between the upper and lower walls of the tank.

[0015] In this manner the pump can draw from the bottom of the tank until it is totally empty without being influenced by any tank deformation.

[0016] The pump is mounted on the flange 2 as follows.

[0017] The elastic element 14 is fixed to the pump 4 by the hose clamp 15, and the elastic cowl 18 is fixed to the pipe stub 19 by one of the two hose clamps 8. The elasticity of the cowl 18 enables it to be folded over temporarily against the pipe stub 19 so that this latter, even though fixed to the elastic cowl 18, can be easily passed through the hole 22 in the base 7 of the pocket 6.

[0018] The pump comes to rest when the elastic element 14 encounters the first projection 13. The elastic cowl 18 is fixed to the pocket 6 by the remaining hose clamp 8 at the second projection 16.

[0019] The combination 1 is ready to be fixed to the tank by screws, not shown, engaging the holes 5. A single block 22 for the electrical connections relative to the level probe and pump 4 can be provided on that surface of the flange 2 facing outwards from the tank.

[0020] The described level probe/feed pump combination 1 can be very easily mounted on the tank and is therefore of merit as it attains its objects in a simple and economical manner. However if for any reason the feed pump 4 is subjected to a force tending to pull it out of the pocket 6 the resistance offered by the elastic cowl 18 along may not be sufficient to resist this. It is hence possible that as a result of vehicle jolting or collision the pump 4 overcomes the resistance offered by an elastic cowl 18 which has undergone ageing.

[0021] This problem is solved by the level probe/feed pump combination of the second embodiment indicated overall by 1A in Figures 3-6. For simplicity, in these figures those elements similar to or in common with the combination 1 of the first embodiment are indicated by the same reference numerals.

[0022] With regard to such similar elements, that already stated with respect to the first embodiment of the combination is therefore valid.

[0023] As can be seen, the first projection 13, the elastic element 14 and the hose clamp 15 which in the first embodiment of the combination 1 formed the means for fixing the upper part of the pump 4 are replaced by a second flange 24, screws 25, a first gasket 26 and a third projection 27. The second flange 24 comprises at least one pair of first annular projections 28 and is prolonged as far as the lateral surface of the feed pump 4. The first gasket 26 is of double "U" cross-section and also comprises at least one pair of second annular projections 29. The second flange 24 is fixed to the first flange 2 by the screws 25. When the flanges 24 and 2 have been fixed, the first gasket 26 has one of its annular projections 29 inserted between the annular projections 28 of the flange 24. The remaining annular projection 29 acts mainly to form a hydraulic seal against the body of the pump 4 and rests against the third projection 27 to provide mechanical locking. When mounting, the first gasket 26 is initially associated with the second flange 24, which is then screwed into position by the screws 25, to lock the pump 4 in its operating position.

[0024] As can be seen, the hose clamp 8, the second projection 16, the edge 17 and the elastic cowl 18 which in the first embodiment of the combination 1 formed the means for fixing the lower part of the pump 4 are replaced by a second gasket 30 and an annular seat 31.

[0025] When mounting, the second gasket 30 is arranged within the annular seat 31 after introducing the tubular element 20 so as to fix it to the base 7 of the pocket 6. The first gasket 26 is initially associated with the second flange 24. The pump 4 is inserted into the pocket 6 such that the pipe stub is locked within the annular seat 31 by the second gasket 30. The second flange 24 is then screwed into position by the screws 25 to lock the pump 4 in its operating position.

[0026] The pump 4 is therefore fixed to and supported on the walls of the pocket 6 by gaskets 26 and 30 which also act as elastic supports and therefore do not transmit the vibration or noise deriving from the operation of the pump 4.

[0027] The pump 4 can therefore not be withdrawn even by being deliberately pulled outwards from the pocket 6, for instance by pulling against the hydraulic and electrical connections emerging from it. This even applies in the case of complete deterioration of the first gasket 5. The third projection 27 would then interfere with the second flange 24 to prevent the pump 4 emerging from the pocket 6.

[0028] In the illustrated embodiment the combination 1A has also been provided with a stilling vessel 32 which can be fixed elastically to the pump 4 so as to be adaptable to the position of the tank base, as can the tubular element 20 by being of telescopic or bellows type.

Claims

1. A level probe/fuel feed pump combination (1) in particular for a motor vehicle tank, comprising a flange (2) to be fixed to the outside edge of an aperture provided in the tank upper wall, to support on that side which is to face the tank interior a level probe (3), characterised in that on that side of said flange (2) which is to face the tank interior there is provided a pocket (6) inside which there is supported via an elastic element (14) the feed pump (4), which dips into the tank in correspondence with the base of said pocket (6), at said point the hydraulic seal between the pump (4) and pocket (6) and their mutual fixing being achieved by interposing between said two elements an elastic cowl (18) fixed at its larger-diameter edge (17) to the pocket (6) and fixed at its smaller-diameter edge (23) to the pump (4).

2. A combination as claimed in claim 1, characterised in that the pocket (6) has a shape obtained by coaxially (10) joining together three aligned tubular elements (9-11) having diameters which progressively decrease towards the base (7), the diameter difference between the first (9) and second (10) tubular element determining a first projection (13) forming a support for the elastic element (14) supporting the pump (4), the diameter difference between the second (10) and third (11) tubular element determining a second projection (16) at which the larger-diameter edge of the elastic cowl (18) is fixed.

3. A combination as claimed in claim 2, characterised in that the elastic support element (14) for the pump (4) has an "L" cross-section, is fixed to the pump body (4) by a hose clamp (15) and rests on the first projection (13).

4. A combination as claimed in claim 2, characterised in that the elastic cowl (18) is of "U" cross-section and is fixed by hose clamps (8).

5. A combination as claimed in claim 1, characterised by comprising a filter (21) upstream of the pump (4) and able to deform elastically by the effect of the variation in distance between the upper wall and lower wall of the tank.

6. A level probe/fuel feed pump combination (1) in particular for a motor vehicle tank, comprising a flange (2) to be fixed to the outside edge of an aperture provided in the tank upper wall, to support on that side which is to face the tank interior a level probe (3), characterised in that on that side of said flange (2) which is to face the tank interior there is provided a pocket (6) inside which there is positioned the fuel feed pump (4), which is elastically fixed at its top by a first gasket (26) provided with second annular projections (29) and interposed between a projection (27) on the pump (4) and a second flange (24) also provided with annular projections (28) and fixed to the first flange (2), said pump (4) dipping into the tank in correspondence with the base of said pocket (6), at said point the hydraulic seal between the pump (4) and pocket (6) and their mutual fixing being achieved by interposing between said two elements a second elastic gasket (30) housed in an annular seat (31) provided on the base (7) of the pocket (6) and simultaneously mounted on a suction pipe stub (19) of the pump (4).

Drawing