DE3132346A1 - LEVEL MEASUREMENT DEVICE IN A FUEL TANK - Google Patents

Description

Dipl.-Ing.

Rolf Charrier ■ ~

Patent attorney

Rehlingenstrasse 8 P.O. Box 260

D-8900 Augsburg 31

Telephone 08 21/3 60 If + 3 öO 16

Telex 53 3 275

! ■ - ■ -.! '». •• .... Itltonta Munich Vr 1547 8 ° 801

8324/115 Augsburg, August 12, 1981

ch-ws

SMITHS INDUSTRIES LI (IITED Crickleuood Works

GB - London NW2 6JN

Level measuring device in a fuel tank

The invention relates to a level measuring device in the case of a fuel tank consisting of a main body, on the one swimmer arm that always carries a tendon is hinged, a main body supporting top plate, which is connectable to the tank and an electrical Circuit, its output signal by the position of the float arm and thus by the level is changed.

Such a level measuring device is described, for example, in GB-PS 941 363. This level measuring device consists of a number of norm or standard parts, which correspond to the different Installation conditions can be connected to one another in different ways. These parts usually consist of a metallic top plate with which the level measuring

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direction can be connected to a tank wall. Farther a carrier is provided and holds an electrical circuit, usually in the form of a potentiometer, which is housed in a metal housing is arranged. A swimmer arm is pivotably linked to this housing and swivels between two stops able. These stops determine the upper and lower position of the float, according to one full and one empty tank. These stops are attached to the aforementioned housing. With the float arm connected is a contact arm, which moves over a potentiometer when the float arm swings and its outcome changed. One or more electrical ones are sealed and insulated through the top plate Connections led. In some applications it is desirable that line connections on the level measuring device for at least one fuel line are provided. A part of the fuel line, which is usually made of metal, runs here, through the top plate. This fuel line part is usually soldered to the top plate. The protruding end of the line is bent over. In such an application, the aforementioned Support arm, which carries the housing for the electrical circuit, is omitted in that this housing is on the inner part of the fuel pipe is arranged.

In such a level measuring device, however, occur has a number of disadvantages. The pivot point of the float arm, the distance between the stops for the float arm, are the length and direction of the float arm

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to be adapted exactly to the respective tank conditions. The assembly of the standard or. Standard parts is therefore very time consuming.

There is the task of the level measuring device to train so that it is easy to manufacture on the one hand, and on the other hand without difficulty to the respective Installation conditions are adaptable.

This task is solved with the features of the claim 1. Advantageous refinements are set out in the subclaims removable.

An exemplary embodiment is explained below with reference to the drawings. Show it:

Fig. 1 is a perspective exploded view of the level measuring device ;

2 shows a section through the main body along the line II-II;

3 shows a section through one of the fuel line connections;

Fig. 4a sections through the threads at the fuel connections and

5a is a view and a section

with the fastening parts for the float arm.

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Fig. 1 shows the main parts of the level measuring device, namely a main body 1, a top plate 2, a connection port 3 for the fuel pipe, a float arm 4, a float arm support 5, a thick film circuit board 6 and a contact arm 7, which has a contact pin 7a, via one or more electrical resistance conductors 24 of the circuit board 6 migrates.

In this embodiment, the main body 1 and the top plate 2 by injection molding made of rigid plastic manufactured in one piece. The plastic used here is not attacked by the fuel. Acts if the fuel is gasoline or diesel fuel, acetal is a suitable plastic material.

The structure of the molded part, its dividing lines and its core parts correspond to the usual injection molding technology.

As can be seen from FIGS. 1 and 2, the main body 1 of the molded part has an open box shape 8, on its base 9 projecting at right angles support surfaces 10 for the thick film circuit board 6 are molded. On the side walls 12 and 13 of the box shape 8 are two elastic inside Claws 11 are provided. These claws 11 are used to hold the plate 6. On the end wall 15 is an im substantially U-shaped claw 14 is provided. During assembly, the claws 11, 14 press the circuit board

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against the wings 10. The claws 11, 14 are arranged so daQ when the circuit board 6 is inserted, this against the support surface 10 and the stop surfaces a and b is printed. The side wall 13 has an inward direction extending incision, which is limited by the inwardly extending walls 16 and 17, which are connected to one another by a side wall 18 of lesser height. This side wall 18 has a hump 19 is provided which has a bore 20 which serves as a pivot axis for the float arm 4. The diminished The height of the wall 18 and the hump 19 gives sufficient play for the assembly of the Schwimmera.rms 4 and its support 5, as will be described below.

The top plate 2 has a connection housing on its upper side 21, in which two connections 22 and 23 are arranged. These electrical connection pins are Injection technology embedded in the molded part. The connection 22 serves as a ground connection, while connection 22a is provided for the connection of a fuel pump is. The connection 23 leads to the fuel gauge during the connection 23a is used to generate a warning signal when the fuel level has reached reserve. As can be seen from FIGS. 1 and 2, the ends of the connections 23, 23a are in the immediate vicinity the support surface 10 of the body 1 and have nose-like projections 25 which make contact with the circuit board 6 and which also serve as claws to hold the circuit board. These nose-like protrusions are soldered to the resistance ladders. The upper surface of the top plate 2 has upwardly protruding pegs

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26 and 27, via which fuel is sucked in and returned u / can earth. These pins 26, 27 are used for connection to line connectors 3. The pins 26,27 each enclose a bore 28,29 through the Upper plate 2. The bore 28 is aligned with a further Bore 28a of larger diameter, which passes through a pipe section 1 a, which is part of the main body 1 is. A fuel intake line can be inserted into this bore 28a 30 are used, at the lower end of which a filter 30a is arranged. It runs concentrically around each peg a cylindrical sleeve 31 of circular cross-section extending from the top of the top plate going upwards. In each cylindrical sleeve 31, a thread 32 is formed by injection molding. This thread is relatively flat and preferably has a slope χ of 1.00 mm. The flank angle pe is for example 30 °. This thread is produced by injection technology, while the manufacture of the molded part in which a core is used which has a suitable thread shape and which passes through after the injection-molded part has been produced Turning out is formed. Only the upper flank is beveled.

As can be seen in FIGS. 1 and 3, a line connecting piece 3 can be connected to each pin, which is preferably also made of plastic, such as acetal. Each connector 3 is provided with an annular plug part 33, which has grooves 34 on the outside. This groove part can also be produced by injection molding and is made by creates a two-part shape. The groove shape is shown in FIG. 4b, the groove lengths being 0.5 mm wide and the distance "is 1.0 mm.

l η

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runs at an angle ö won 45 °. The other flank of the groove runs at right angles · The thread of the sockets 31 has threads that lead in the other direction are beveled, with the other thread flank running at right angles. The parts according to Fig. 4a and 4b are mirror images of one another with respect to a horizontal line. The bore 35 of the plug part 33 is stepped, as is the outer surface of the respective pin 26 or 27. Between the An O-ring 36 is used for sealing. The illustrated design of the parts 32 and 34 of the journals 26 and 27 and the connecting parts 3, a gas- and liquid-tight screw connection is achieved, which is nevertheless easy to assemble and dismantle. The angles CK and (S ^ are of particular importance. Im In the assembled state, a firm plug connection is achieved. The parts 32 and 34 hook into one another and prevent loosening of the connecting part 3. The result is a strong and secure plug connection. Each line connecting part 3 is connected to a pin part 37 to which a fuel line is connectable. These pin parts 37 run at right angles to the plug part 33. According to the installation conditions the pin parts can point in a certain direction. This direction preferably runs radial. Tests have shown that the parts 32 and 34 secure the connecting part x 3 against rotation to back up.

The Schuimmerarm 4 is middle of the float arm support 5 attached. This carrier is also made of art

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8324/115 - 11-12 August 1981

fabric and has a substantially U-shaped shape. The middle leg is denoted by 38 and the two parallel legs 39 and 40. The parallel extending arms 39 and 40 are provided with two aligned bores 41, 41 'from the bore A wedge-shaped slot 42 extends from 41. The outer surface of the leg 40 has two projections 43, 44 on, each of which has a bore 45 to which a slot 46 leads.

As can be seen in particular from FIG. 5b, the Sehwimmerarm 4 is bent at right angles and thus has a connecting arm 47. The carrier 5 is above the Mounted boss 19 of the main body 1 in such a way that the bores of the side arms 39 and 40 with the bore 20 cursing. The contact arm 7, which also has a bore 48, is between the side surface of the boss 19 and the arm 40 arranged with its bore aligned with the other bores. Like Figures 1 and 5b can be removed, the connection end 49 of the ground connection 22 extends downwards and is in contact with the Contact arm 7. The connection arm 47 of the float arm 4 is after the support part 5 is placed on the boss 19, wherein the contact arm 7 is held between the boss and the support part 5, inserted through the bores, the The float arm engages with one of the two bores 45 of the projections 43; 44. As best shown in FIG. 5a is, the float arm 4 is able to pivot together with the carrier 5 about the axis of the fastening arm 47. In this case, it moves in the area of a section 50 of the wall 12. As FIG. 2 shows, part of the

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8324/115,.,, " _Λ . _1QO1

- August 12 - 12, 1981

Cut when manufacturing the molded part by injection molding manufactured. This cutout has an upper inclined stop surface 51, whereby a Reference position of the float arm 4 is defined. The Schvi / Immerarm 4 is here connected to the projection 43. This upper stop position corresponds to the position when the fuel tank is full. The lower stop edge of the cutout 50 can be formed and / or grounded by severing of material from the wall 12. This allows a lower stop edge to be defined, which the Construction conditions of the fuel tank is adaptable. The lower stop edge defines the arc through which the float arm 4 can pivot downward from its reference position, the lower one Stop position corresponds to an empty tank. The size of the cutout 50 is thus due to a decrease in material on the lower edge of the cutout, the respective installation conditions, i.e. the proportions of the Adapted fuel tanks. The sheet / 3 in Fig. 5a through the float arm 4 can swing, is taken part of the contact arm 7, which in this case via the resistance ladder 24 of the circuit board 6 migrates. In this way, the only signal that changes is fed to the fuel gauge.

As mentioned above, the 0 or reference position depends of the arm 4 and the arc that this arm 4 can walk through, depending on the special installation conditions, i.e. on the shape of the tank, on whether the level measuring device on a side wall or the top wall

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8324/115 - August 13 - 12, 1981

of the tank is arranged, etc. In order to be able to adapt the level measuring device to the various installation conditions, the two projections 43 and 44 are provided, into which the arm 4 can be optionally inserted. Another possibility of variation results in that the cutout 50 is made larger or smaller by removing material from the viand 12. In this way, the position of the arm 4 is determined according to a full and an empty tank. In order to facilitate this adaptability, a slot 52 is formed in the side wall 12, which forms an upper stop edge 53 which determines a reference position of the float arm when it is inserted into the projection 44. If the arm is inserted into this projection 44 4 _s then it may be necessary to cut out a part of the end wall 15 to form the lower stop for the arm there.

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Claims (1)

Dipl.-Ing. Rolf Charrier Patent attorney Rehlinyenstraße8 - P.O. Box 26 « D-89ÜU Augsburg 31
Telephone 0821/36015 + 36016 Telex 533275 _Anftu . _SMITHS INDUSTRIES LIMITED · "Vv.hemk.jnio Munich No. i? 4 * 89-S (H., Ion l ι r> η ι 8324115 Augsburg, August 12, 1981 ch-ws Expectations 1.) Level measuring device in a fuel tank, consisting of a main body to which a float arm carrying a float is articulated, one the main body supporting top plate, which is connectable to the tank and an electrical circuit, its output signal through the position of the shoe arm and is thus changed by the level, characterized in that the top plate (2) is designed as a one-piece plastic injection-molded part, this plate (2) with at least one Pin (26,27) is provided, which serves to receive a fuel line connecting part (3) through this pin (26,27) has a bore (28,29) which passes through the top plate (2; the The pin (26,27) is concentrically surrounded by a cylindrical sleeve (31) which has an internal toothing (32) which can be locked with external teeth (34) on the plug part (33) of the connecting part (3) is, the permanent latching takes place by inserting the plug part (33) into the sleeve (31). 2. Heßvorrichtung according to claim 1, characterized in that each fuel connecting part (3) a pin (37) for connecting a fuel 8324/115 - 2 - August 12, 1981 has line, this pin (37) runs at an angle to the plug part (33), the teeth (32,34) snap together as a holding seat in such a way that the connecting part (3) relative / to the plate (2) does not is rotatable. Measuring device according to Claim 1 or 2, characterized in that the one toothing consists of parallel grooves running closely next to one another, which have a sloping lead-in flank have and the other toothing consists of a thread which has a low pitch having. Measuring device according to claim 3, characterized in that the internal toothing (32) has the shape of a flat thread, uelches is technically molded on the inside of the cylindrical sleeve (3i) and the external toothing (34) on the plug part (33) has the shape of mutually parallel grooves. Measuring device according to claim 3 or 4, characterized in that the thread (32) has a pitch of x = 1.00 mm, the flank of which facing the insertion side is at an angle is inclined by <X = 30 and that the mutually parallel Grooves of the external toothing (34) have a distance from one another of 1.00 mm, their width 0.5 mm and the flank pointing in the direction of the sleeve runs at an angle S1 of 45. 8324/115 - 3 - August 12, 1981 ch- \ i / s 6. MeG device according to one of claims 1 to 5, characterized in that between the pin (26,27) and the plug part (33)
Sealing ring (36) is arranged. 7. HeQ device according to one of claims 1 to 6, characterized in that the top plate (2) and the main body (1) from one one-piece molded part exist.