Title of Invention

A LEVEL SENSOR

Abstract This invention relates to a level sensor (2) for generating electrical signals as a function of a pivoting angle of a lever arm (3) with a float (4) for a tank of a motor vehicle, comprising a carrier (6,25) provided for fastening to a lateral wall in the tank; a yoke (5,28) made of plastic and pivotable in a mounting (11, 31) of the carrier (6), a lever wire (7) holding the float (4) and fastened to the yoke (5); and a guide rail (16, 32) arranged on the carrier (6), for guiding a guide element (12,13,33) of the yoke (5,28) in an intended axial position In relation to the carrier (6). The guide rail (16, 32) is arranged so as to point in the direction of the mounting (11, 31) and in that the yoke (5, 28) has a fork-shaped guide element (12, 13, 33) which is open at its end facing away from the mounting (11, 31) and which is in engagement with the guide rail (13, 32)
Full Text 1
FIELD Of THE INVENTION
The invention relates to a filling-level sensor for generating electrical signals as a function of a pivoting angle of a float-carrying lever arm for a tank of a motor vehicle, with a carrier provided for fastening to a lateral wall in the tank, with a yoke made from plastic and pivotable in the mounting of the carrier, with a lever wire holding the float and fastened to the yoke, and with a guide rail, arranged on the carrier, for guiding a guide element of the yoke in an intended axial position in relation to the carrier,
BACKGROUND OF THE INVENTION
Such filing-level sensors usually have a potentiometer with a wiping track arranged on the carrier and with wiper contacts, fastened to the yoke, for generating the electrical signals and are known from practice. Alternatively to this, the electrical signals are often also generated by means of a magnetically active position sensor. Magnetically active position sensors mostly have a resistance network which is to be fastened to the carrier and which is switchable by a magnet arranged on the yoke. The tank may be, for example, a fuel tank or a washing-water tank of a windshield cleaning system. The guide rail of the known filling-level sensor is designed as part of the carrier having a plane surface and is oriented away from the mounting. A U-shaped guide element arranged on the yoke engages behind the guide rail. This, in the case of lateral forces acting on the yoke and the lever wire, prevents the yoke from being bent away from the carrier and therefore the wiper contacts from being lifted off from the wiping track or the magnet from being removed from the resistance network.

2
One disadvantages of the known filling-level sensor is that, because of the guide element, the yoke has very large dimensions and therefore a high weight. As a result, the center of gravity of the yoke is at a very great distance from the mounting, and therefore the filling-level sensor is very slow-acting. Consequently, minor variations in the filling level are detected by the potentiometer only with a delay or abruptly. Moreover, because of the high weight of the yoke, the latter requires a large quantity of material.
DE 19754521 discloses a yoke (3) having a connecting element (22) being connected to a coupling element (21), which acts as a connection between the yoke (3) and a holding element (20). The yoke (3), the coupling element (22) and the holding element (20) are three separate parts. Further the holding element (20) has two separate fork-shape areas on both sides. Although the holdings element (20) is guided, the yoke (3) is not guided.
OBJECT OF THE INVENTION
It is therefore an object of the invention to propose a filling-level sensor of the type mentioned in the introduction, in such a way that it detects a variation in the filling level particularly quickly and is constructed cost-effectively.
SUMMARY OF THE INVENTION
Accordingly there is provided a filling-level sensor in which the guide rail is arranged so as to point in the direction of the mounting, the yoke has a fork-shaped guide element which is open at its end facing away from the mounting and is in engagement with a guide rail.

2A
By virtue of this design, the yoke has very small dimensions and a particularly low weight. Moreover, the center of gravity of the yoke is arranged \/er/ near the mounting, so that said yoke has particularly low inertia. The yoke can therefore follow a variation in the filling level in the tank particularly quickly. Due to the low weight of the yoke, the latter necessitates the use of a correspondingly small amount of material, so that it can be produced particularly cost-effectively.

3
The guide rail could, for example, have a- round cross section. However, according to an advantageous development of the invention, the carrier can be manufactured at a pa'rticularly low outlay in one piece with the guide rail from plastic by the injectioit molding method if the guide rail has a web-shaped configuration and is arranged parallel to the carrier. By virtue of this configuration, the guide rail has a sliding track for the guide element on each of the two sides.
The fork-shaped guide element could, for example, be arranged in a middle region of the yoke. However, a contribution to further reducing the dimensions of the yoke is made when the fork-shaped guide element is arranged at that end of the yoke which faces away from the mounting.
The yoke is particularly reliably mounted on the carrier axially and can nevertheless be mounted on the carrier very simply when it is designed to engage around at least part of the carrier in the region of the mounting. For mounting, the yoke can simply be pushed over the carrier from the mounting. The yoke is subsequently guided axially in the region of the mounting and on the guide rail.
To prevent the yoke from tilting, the guide element may be made particularly wide. However, because of this, the guide element has a high weight and a large bearing surface on the guide rail. The large bearing surface leads to undesirable frictional losses during the pivoting movement of the yoke. According to another advantageous development of the invention, a tilting of the yoke can be prevented in a simple way by means of two fork-shaped guide elements arranged next to one another, without the weight of the yoke being appreciably increased thereby.

4
According to another advantageous development of the invention, the yoke is mounted in a particularly simple way when a spring element prestressing the wiper contact against the wiping track of the potentiometer is fastened between the guide elements arranged next to one another.
A deformation of the guide rail could lead to the wiper contact being lifted off from the wiping track or to a rubbing of the guide element. According to another advantageous development of the invention, the guide rail has very high stability when it has a projecting edge.
The hHing-level sensor according to the invention is manufactured particularly cost-effectively when the guide rail is at a greater or equal distance from the carrier at its end facing away from the mounting than at its end facing the mounting, and when surfaces of the carrier and of the guide rail which face one another in each case have a plane configuration. By virtue of this configuration, the carrier can be manufactured, together with the guide rait, in a very simple way from plastic by the injection molding method in an injection mold from which removal can easily take place axially.
According to another advantageous development of the invention, the carrier requires the use of a particularly small amount of material when the guide rail is held at its ends by holding parts in front of the carrier.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The invention permits numerous embodiments. In order to make its basic principle even clearer, two of these are illustrated in the accompanying drawings and are described below. In the accompanying drawings ;

5
Fig. 1 shows a -perspective illustration of a filling-level sensor according to the invention.
Fig. 2 shows a sectional illustration through the filling-level sensor from Figure 1 along the line II-II,
Fig. 3 shows a further embodiment of the filling-level sensor according to the invention in a longitudinal section through a yoke.
DETAIL DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
Figure 1 shows a filling-level sensor 2 according to the invention, mounted on a vertical wall 1 within a fuel tank. The filling-level sensor 2 has a float 4 fastened to a lever arm 3. The lever arm 3 is mounted pivotably on a carrier 6 by means of a yoke 5 made from plastic and has a lever wire 7, fastened to the yoke 5, for holding the float 4. The float 4 follows a fuel level in the fuel tank and at the same time pivots the lever arm 3. The pivoting angle of the lever arm 3 is detected by a potentiomerter 8. The potentiometer 8 has two wiping tracks 9 arranged on the carrier 6 and a wiper contact 10 fastened to the yoke 5. The wiper contact 10 is designed as a double contact for bridging the wiping tracks 9. To guide the yoke 5 in an intended axial position in relation to the carrier 6, the yoke 5 engages behind the carrier 6 in the region of a mounting 11. The yoke 5 has, at its end facing away from the mounting 11, two fork-shaped guide elements 12, 13 which are arranged next to one another and which are in engagement with a guide rail 16 fastened laterally to the carrier 6 by means of holding parts 14, 15. By yoke 5 being guided in the intended axial position in

6
relation to the carrier 6, the wiper contact 10 is reliably prevented from being lifted off from the wiping tracks 9.
Figure 2 shows a filling-level sensor 2 according to the invention from figure 1 in a sectional illustration along the line II-II. It can be seen here that the lever wire 7 forms, in the region of the mounting 11 of the yoke 5, an angled portion 17 functioning as a bearing axle for the lever arm 3. The carrier 6 has a bearing bore 18 comprising two parts 19,20. A free end of an engaging-around portion 21 of the yoke 5 is arranged between the two parts 19, 20 of the bearing bore. The wiper contact 10 is prestressed against the wiping tracks 9 by a tongue-shaped spring element 22. The tongue-shaped spring element 22 is fastened to the yoke 5 between to two fork-shaped guide elements 12, 13. To increase the stability of the guide rail 16, the latter has two vertically projecting edges 23,24.
Figure 3 shows a further embodiment of the filling-level sensor according to the invention, with a lever arm 26 pivotable on a carrier 25 in a mounting 31. The lever arm 26 has a yoke 28 snapped together with a lever wire 27. The carrier 25, here, has a one-part bearing bore-29, behind which an angled portion 30 of the yoke 28 is engaged. At the end facing away from the mounting 31, the yoke 28 has a fork-shaped guide element 33 which is in engagement with a guide rail 32 of the carrier 25. The guide rail 32 and a region of the carrier 25 which faces the guide rail 32 has plane surfaces 34,35 arranged parallel to one another.

7
WE CLAIM
1. A level sensor (2) for generating electrical signals as a function of a pivoting angle of a lever arm (3) with a float (4) for a tank of a motor vehicle, comprising a carrier (6,25) provided for fastening to a lateral wall in the tank; a yoke (5,28) made of plastic and pivotabie in a mounting (11,31) of the carrier (6), a lever wire (7) holding the float (4) and fastened to the yoke (5); and a guide rail (16,32) arranged on the carrier (6), for guiding a guide element (12,13,33) of the yoke (5,28) in an intended axial position in relation to the carrier (6), characterized in that the guide rail (16,32) is arranged so as to point in the direction of the mounting (11, 31) and in that the yoke (5,28) has a fork-shaped guide element (12,13,33) which is open at its end facing away from the mounting (11,31) and which is in engagement with the guide rail (13,32).
2. The level sensor as claimed in claim 1, wherein the guide rail (16,32) has a web-shaped configuration and is arranged parallel to the carrier (6,25).
3. The level sensor as claimed in claim 1 or 2, wherein the fork-shaped guide element (12,13,33) is arranged at that end of the yoke (5,28) which faces away from the mounting (11,31).
4. The level sensor as claimed in one of the preceding claims, wherein the yoke (5,28) is configured to engage around at least part of the carrier (6,25) in the region of the mounting (11, 31).

8

The level sensor as claimed in one of the preceding claims, comprising two fork-shaped guide elements (12,13) arranged next to one another.
The level sensor as claimed in claim 1, comprising a potentiometer (8) having atleast two wiping tracks (9) arranged on the carrier (6), and a wiper contact (10) fastened to the year (5).
The level sensor as claimed in one of the preceding claims, wherein a spring element (22) prestressing the wiper contact (10) against the wiping track (9) of the potentiometer (8) is fastened between the guide elements (12,13) arranged next to one another.
The level sensor as claimed in one of the preceding claims, wherein the guide rail (16) has a projecting edge (23, 24).
The level sensor as claimed in one of the preceding claims, wherein the guide rail (32) is at a greater or equal distance from the carrier (25) at its end facing away from the mounting (31) than its end facing the mounting (31), and wherein surfaces (34,35) of the carrier (25) and of the guide rail (32) which face one another in each case have a plane configuration.

The level sensor as claimed in one of the preceding claims, wherein the guide rail (16) is held at its ends by holding parts (14,15) in front of the carrier (6).
This invention relates to a level sensor (2) for generating electrical signals as a function of a pivoting angle of a lever arm (3) with a float (4) for a tank of a motor vehicle, comprising a carrier (6,25) provided for fastening to a lateral wall in the tank; a yoke (5,28) made of plastic and pivotable in a mounting (11, 31) of the carrier (6), a lever wire (7) holding the float (4) and fastened to the yoke (5); and a guide rail (16, 32) arranged on the carrier (6), for guiding a guide element (12,13,33) of the yoke (5,28) in an intended axial position In relation to the carrier (6). The guide rail (16, 32) is arranged so as to point in the direction of the mounting (11, 31) and in that the yoke (5, 28) has a fork-shaped guide element (12, 13, 33) which is open at its end facing away from the mounting (11, 31) and which is in engagement with the guide rail (13, 32)

Documents:

00695-kolnp-2003 abstract.pdf

00695-kolnp-2003 claims.pdf

00695-kolnp-2003 correspondence.pdf

00695-kolnp-2003 description(complete).pdf

00695-kolnp-2003 drawings.pdf

00695-kolnp-2003 form-1.pdf

00695-kolnp-2003 form-18.pdf

00695-kolnp-2003 form-2.pdf

00695-kolnp-2003 form-3.pdf

00695-kolnp-2003 form-5.pdf

00695-kolnp-2003 g.p.a.pdf

00695-kolnp-2003 letters patent.pdf

00695-kolnp-2003 priority document.pdf

695-KOLNP-2003-ASSIGNMENT.pdf

695-KOLNP-2003-CORRESPONDENCE 1.1.pdf

695-kolnp-2003-granted-abstract.pdf

695-kolnp-2003-granted-claims.pdf

695-kolnp-2003-granted-correspondence.pdf

695-kolnp-2003-granted-description (complete).pdf

695-kolnp-2003-granted-drawings.pdf

695-kolnp-2003-granted-examination report.pdf

695-kolnp-2003-granted-form 1.pdf

695-kolnp-2003-granted-form 18.pdf

695-kolnp-2003-granted-form 2.pdf

695-kolnp-2003-granted-form 3.pdf

695-kolnp-2003-granted-form 5.pdf

695-kolnp-2003-granted-gpa.pdf

695-kolnp-2003-granted-letter patent.pdf

695-kolnp-2003-granted-priority document.pdf

695-kolnp-2003-granted-reply to examination report.pdf

695-kolnp-2003-granted-specification.pdf

695-kolnp-2003-granted-translated copy of priority document.pdf


Patent Number 213658
Indian Patent Application Number 695/KOLNP/2003
PG Journal Number 02/2008
Publication Date 11-Jan-2008
Grant Date 09-Jan-2008
Date of Filing 30-May-2003
Name of Patentee SIEMENS AKTIENGESELLSCHAFT
Applicant Address WITTELSBACHERPLATZ 2, 80333 MUNICH
Inventors:
# Inventor's Name Inventor's Address
1 BOUTON STEPHANE 36 RUE SAINT-GERMAIN, F-57300 PONTPIERRE
2 GETTE CHRISTOPHE 4, RUE LES TARREAUX F-57245 MECLEUVES
3 KORST OTTO HEBELGARTEN 4, 56414 HERSCHBACH
PCT International Classification Number G01 F 23/32
PCT International Application Number PCT/DE01/04729
PCT International Filing date 2001-12-17
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 100 64 591.7 2000-12-22 Germany