Pump for selectively feeding the front windscreen washer and rear window washer of a vehicle

Abstract

 The pump (1) is provided with a substantially cylindrical pump casing (2) provided with an axial suction duct (4) and opposing tangential delivery ducts (5, 6) and with an impeller (7) housed in the pump casing (2) coaxial to the suction duct (4); the delivery ducts (5, 6) are both provided with respective automatic non-return valves (15) arranged to selectively allow a unidirectional flow in one of the delivery ducts (5, 6) in accordance with the direction of rotation of the impeller (7).

Description

[0001] This invention relates to a pump for selectively feeding the front windscreen washer and rear window washer of a vehicle, in particular a motor vehicle.

[0002] The front windscreen and rear window washers of a vehicle are currently fed with wash liquid by two different pumps driven by respective electric motors controlled by one or two switches situated inside the vehicle, and arranged to withdraw the wash liquid from the inside of a container common to both washers in order to feed it to these latter through suitable tubes. In order to reduce the cost and weight of the aforesaid feed device for the windscreen and rear window washers of a vehicle, it has been proposed to use a single pump driven by a reversible motor and provided with two opposing coaxial facing delivery ducts arranged to be selectively opened or closed, according to the direction of rotation of the pump impeller, by means of an automatic wing valve disposed in the pump chamber occupied by the impeller and bounded by the pump casing, and hinged coaxial with the impeller itself. Although this method enables a single pump driven by a single motor to be used, it is not totally reliable in that the wing valve is not always instantly operated by the fluid flow produced by the impeller and/or by a suitable control system. Moreover, this method requires special pumps to be constructed in which the pump casing is provided with the space necessary for housing the wing valve, can lead to local pressure drops and/or disturbances in the flow of wash fluid through the pump, and in particular requires the construction of pumps in which the two delivery ducts face each other and are coaxial, so as to be able to be alternately closed by the same valve. This latter drawback can create space problems in a situation in which it would be preferable for the two delivery duets not to be coaxial but, for example, to be disposed offset at an angle to each other. The object of the present invention is to provide a pump for selectively feeding the front windscreen washer and rear window washer of a vehicle, of the type heretofore described, ie provided with a reversible motor, which is free from the aforesaid drawbacks and in particular is of reliable operation and able to allow the opposing delivery ducts to assume any arrangement relative to each other, and moreover is provided with an impeller chamber which is occupied only by the impeller itself.

[0003] The aforesaid objects are attained according to the present invention by a pump for selectively feeding the front windscreen washer and rear window washer of a vehicle, in particular a motor vehicle, of the type comprising a substantially cylindrical pump easing provided with an axial suction duct and two substantially tangential delivery duets, and with an impeller housed inside said pump casing and disposed coaxial to said suction duct, said impelier being arranged for operation by a revereible motor controlled by a switch, cbarac- terised in that each of said delivery ducts is provided with an automatic non-return valve, said non-return valves being arranged to selectively allow a unidirectional flow in one of said delivery ducts in accordance with the direction of rotation of said impeller. The present invention will be more apparent from the non-limiting description of two embodiments with reference to the accompanying drawings in which:

Figure 1 is a cross-section through a pump in accordance with the present invention;

Figure 2 shows a simplified control scheme for the pump of Figure 1: and

Figure 3 shows a modification of the pump of Figure 1.

[0004] In Figure 1, the reference numeral 1 indicates overall a pump for selectively feeding a wash liquid, for example a solution of water and detergent contained in a vessel la illustrated by dashed lines and on which the pump 1 is fixed, to a known front windscreen washer and rear window washer, not shown, of any known vehicle, also not shown, for example a motor vehicle. The pump 1 comprises a substantially cylindrical pump casing 2 defining internally a pump chamber 3 and provided with an axial suction duct 4 and two opposing tangential delivery ducts 5, 6 respectively, and an impeller 7 housed in the casing 2 inside the chamber 3, and disposed coaxial to said duct 4. The impeller 7 comprises a plurality of radial blades 8 (four in the illustrated example) preferably fixed on to and angularly rigid with a rotary shaft 9 supported by suitable known bearings, not shown, and coupled in an angularly rigid known manner, not shown, to a reversible motor, preferably electric, indicated by 10 in Figure 2. The motor 10 is coaxial to the shaft 9 and duct 4, and is controlled by a switch indicated overall by 11 in Figure 2, to be operated by the vehicle user and situated for example inside the passenger compartment thereof, the impeller 7 being arranged for reversible operation by the motor 10, ie in both directions of rotation illustrated by the arrows in Figures 1 and 2. The casing 2 and motor 10 are preferably mounted coaxial on the outside of the Vessel la, and the chamber 3 is connected to the interior of this latter by the duct 4.

[0005] The duets 5 and 6 are preferably integral with the casing 3, for example of plastics construction, and each comprises opposing ends 12 and 13 which terminate respectively in the chamber 3 inside the pump casing 2 and at a respective connection nipple 14. The nipples 14 are integral with the ducts 5 and 6 at the end of these latter, and can be connected in a fluid-tight manner to respective flexible pipes, not shown, connected respectively to said front windscreen washer and rear window washer.

[0006] According to the invention, the dicts 5 and 6 are also each provided with a respective automatic non-return valve 15 arranged to selectively allow a unidirectional flow in the respective delivery duct 5 or 6 in accordance with the direction of rotation of the impeller 7.

[0007] Each valve 15 comprises a housing 16 provided in the corresponding delivery duct 5 or 6 between the opposing ends 12 and 13 thereof, and constituted by a widening-out thereof, a valve ball 18 housed mobile in the respective housing 16 and arranged to cooperate in a fluid-tight manner with a respective valve seat 19 provided in the housing 16 on that side facing the pump casing 2, and preferably a helical spring 20, for example conical, arranged to retain the ball 18 against the respective seat 19 under predetermined presaure. Preferably, the valves 15 comprise springs 20 of such a rating as to require an opening pressure of between approximately 0.3 and 0.4 kg/cm², so as to open only when in the respective end 12 there is exerted an overpressure of this extent by virtue of the movement of the impeller 7. As shown in Figure 2, the switch 11 can comprise a change-over switching mechanism 21 arranged to connect respective pairs of contacts 23 and 24 to respective feed terminals 22 in order to feed a feed circuit 25 for the motor 10. The change-ever switching mechanism 21 can obviously assume three positions, namely a neutral position shown in Figure 2 in which it does not connect either of the pairs of contacts 23 or 24 to the terminals 22, a first switching position in which it connects the terminals 22 to the pair of contacts 23 in order to cause the motor 10 to rotate in a predetermined direction, and a second switching position in which it connects the terminals 22 to the pair of contacts 24 in order to cause the motor 10 to rotate in the opposite direction. The operation of the pump 1 heretofore described is as follows. When the switch 11 is in the position shown in Figure 2 the motor 10 is at rest and consequently the impeller 7 is at rest and the pump 1 is not working. Both the ducts 5 and 6 are closed in a fluid-tight manner by the respective valves 15, even if the pump 1 is disposed below the liquid level and is thus constantly filled with the liquid contained in the vessel la. Thus in such a position it is not necessary, because of the valves 15, to provide the pump 1 with any further shut-off valve, for example in the duct 4. On operating the switch 11, the user is able to cause the pump 1 to selectively feed the front windscreen washer or rear window washer, which are connected respectively to the ducts 5 and 6 by way of the said pipes, not shown. In this respect, when the switch 11 connects the terminals 22 to the contacts 23, the motor 10 rotates, for example clockwise, to drive the impeller 7 in the same direction of rotation so that it centrifunes the liquid contained in the compartment 3 towards the end 12 of the duct 6, while at the same time drawing new liquid from the interior of the vessel la through the duct 4. This fluid movement produced by the impeller 7 obviously produces an increase in pressure at the end 12 of the duct 6 and a decrease in pressure at the end 12 of the duct 5. Consequently the valve 15 of the duct 6 opens to allow feed to the end 13 and thus to the rear window washer, whereas the valve 15 of the duct 5 increases its own closure pressure and prevents any feed of detergent liquid to the front windscreen washer. In order to feed detergent liquid to this latter, the switch 11 is switched-over by moving the change-over switching mechanism 21 in such a manner as to connect the pair of contacts 24 to the terminals 22. In this case, the motor 10 and impeller 7 are rotated anti-clockwise in order, as heretofore described, to create an overpressure at the end 12 of the duct 5, which causes opening of the relative valve 15, thus feeding the front windscreen washer through the end 13.

[0008] Figure 3 shows a possible modification 30 of the pump 1 of Figure I, parts similar or equal to those already described being indicated for simplicity by the same reference numerals. Specifically, the pump 30 differs from the pump 1 by the arrangement of the ducts 5 and 6, which instead of being disposed tangentia1 to the chamber 3 and coaxial and facing each other, they are disposed parallel and side- by-side, so that the two ends project from the same portion 31 of the casing 3. In this manner, the pump 30 has a reduced overall size and in any case much less than that of the pump 1. The balls 18 of the valves 15 of the pump 30 can be retained against the respective valve seats 19 by springs analogous to the springs 20, or alternatively, as shown in Figure 3, they can be fixed rigidly to suitably pre-loaded helical tension springs 3? fixed to the opposing ends of an equaliser rod 33 connected to the portion 31 of the casing 3.

[0009] The operation of the pump 30 is identical to the operation of the numn 1 as heretofore described, and requires a feed circuit 25 and switch 11 such as those described. The pressure increase at the end 12 of one of the ducts 5 and 6 causes the relative valve 15 to open and place the spring 32 under tension, whereas the other valve 19 remains closed.

[0010] The advantages of the present invention are apparent from the aforegoing description. Firstly, compared with current methods it enables one pump and one electric motor to be eliminated, thus resulting in feed devices for the front windscreen washer and rear window washer which are simplified and of reduced weight. Secondly, compared with analogous reversible pumps of the known art, the pump of the present invention is of lower cost and simpler construction, in that the pump casino is substantially the same as the casing of current single-delivery pumps (ie having only one delivery duct), and does not use a special automatic valve, but instead uses common commercially available non-return valves which are of reliable operation, of very low cost and very light in weight. Furthermore, in the pump according to the invention, the pump compartement is kept completely free of any supplementary device and is occupied only by the impeller, thus preventing the creation of disturbances to the flow of wash fluid and/or creating local pressure drops. Finally, and most important, in the pump according to the present invention it is not necessary for the delivery ducts 5 or 6 to be perfectly tangential, coaxial and facing each other, as in the case of known reversible pumps, but instead they can be disposed on the same side, as in Figure 3, or offset and oblique to each other, ie inclined at a certain angle, according to the design space requirements to be satisfied at any given time. In this respect, the presence of two separate valves each disposed in a respective duct allows widest possible design freedom in the arrangement of these latter, in contrast to known reversible pumps.

[0011] Finally, from the description it is apparent that modifications can be made to the described pump according to the present invention without leaving the scope of the invention itself. For example, the pump 1 can be volumetric or centrifugal, and the impeller 7 could also be of the mobile blade, positive displacement or any other known type.

Claims

1. A pump (1, 30) for selectively feeding the front windscreen washer and rear window washer of a vehicle, in particular a motor vehicle, of the type comprising a substantially cylindrical pump casing (2) provided with an axial suction duct (4) and two substantially tangential delivery ducts (5, 6), and an impeller (7) housed inside said pump casing (2) and disposed coaxial to said suction duct (4), said impeller (7) being arranged for operation by a reversible motor (10) controlled by a switch (11), characterised in that each of said delivery ducts (5, 6) is provided with an automatic non-return valve (15), said non-return valves (15) being arranged to selectively allow a unidirectional flow in one of said delivery ducts (5, 6) in accordancewith the direction of rotation of said impeller (7).

2. A pump (1, 30) as claimed in claim 1, characterised in that said non-return valves (15) have an opening pressure of between approximately 0.3 and 0.4 kg/cm².

3. A pump (1, 3n) as claimed in claim 1 or 2, characterised in that each of said non-return valves (15) comprises a housing (16) formed in the corresponding delivery duct (5, 6) between opposite ends thereof (12, 13) which open into said pump casing (2) and at a connection nipple (14) on said delivery duct (5, 6) respectively, and constituted by a widening-out of this latter, and a valve ball (18) housed mobile in said housing (16) and arranged to cooperate in a fluid-tight manner with a valve seat (19) disposed on the same side as the pump casing (2).

4. A pump (1, 30) as claimed in claim 3, characterised in that each of said non-return valves (15) comprises a spring (20, 32) arranged to retain said ball (18) against said seat (19) under a predetermined pressure.

5. A pump (1, 30) as claimed in one of the preceding claims, characterised in that said impeller (7) comprises a plurality of radial blades (8) mounted on a rotating shaft (9) counted to said reversible motor (10) and coaxial to said suction duct (4), said pump casing (2) defining a pump chamber (3) occupied only by said impeller (7).

Drawing