JPS6126608B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention comprises a float having a central aperture, a guide rod extending through the aperture, and a conductive winding supported along substantially its entire length by the guide rod. at least one conductive vane supported in movable contact with the winding by a float; an outer tube whose bottom is secured to the lower end of the guide rod and surrounds the float; and one end of the conductive vane and the winding connected to an output terminal. The present invention relates to a liquid level gauge, in particular intended for use in vehicle tanks, with electrical connections for connection to the respective terminals.

This type of liquid level gauge is known, for example, in the French patent No.
The one described in specification No. 2115093 is well known. The resistance of the winding varies with the position of the float and thus the level of the liquid in the tank, allowing the level to be indicated on a visual display device. When the liquid level reaches a predetermined minimum amount corresponding to a given distance traveled by the vehicle, it is necessary to draw the driver's attention, for example by means of a signal lamp. For this purpose, a contact supported by a float and a fixed contact provided at the bottom of the tube,
A warning circuit is provided which closes when the contacts are brought into contacting engagement with each other.

Various solutions have been proposed for creating warning devices. According to one proposal, contact engagement occurs when a contact supported by a float engages another contact. Such a solution has the disadvantage that the float cannot move further downwards beyond the warning position, and the liquid level between the warning value and the zero position cannot be displayed. According to another proposal, the fixed contact is a vane on which the float contact can slide, allowing the float to move down beyond the warning position. However, adjusting the attachment of the blades is difficult and must be done by hand. Also, this solution requires a defined angular position of the float, making assembly more complex.

The object of the invention is to provide a level gauge that does not have the disadvantages pointed out in the known solutions. In accordance with the invention, in a level gauge of the type specified, the contact supported by the float is an electrically conductive rod capable of sliding in a hole formed in the float, the hole having its axis aligned with the axis of the guide rod. The conductive rod supports the holding member at its upper end, and is roughly parallel to the
The fixed contact is in the form of an electrically conductive surface located at the bottom of the tube.

The use in accordance with the present invention of a slidable rod as a contact supported by a float allows the float to move downwardly beyond the warning position. Furthermore, no installation adjustments are required, and the warning position is determined solely by the length of the conductive rod portion that projects from the float.

The invention will become more apparent from the following detailed description of preferred embodiments of the invention, taken in conjunction with the accompanying drawings.

The level gauge for a vehicle fuel tank shown in the drawings has an outer tube 1 provided with a bottom portion 2 and a cover 3, and a winding 5 provided along the axis of the outer tube 1 and extending over the entire outer surface. It mainly consists of a guide rod 4 and a float 6 which is provided inside the outer tube 1 and has a central opening through which the guide rod 4 extends.

The outer tube 1 is provided with a hole (not shown) forming a passage for fuel at a position slightly above the bottom portion 2 thereof.
This hole is sufficiently smaller than the outer tube 1 so as to make the anti-wave-making device effective.

The float 6 is provided on its inner periphery with contact vanes 7 which engage in sliding engagement with the winding 5 supported by the guide rod 4.

The contact vanes 7 are connected by suitable means, not shown, to a strip 8 supported by a screw 9 which is in electrical contact with one end of a spiral spiral member 10 made of contact material. The other end of the spiral member 10 is connected to a connecting terminal 11 fixed to the cover 3 of the outer tube 1.

The upper end of the winding 5 is connected to a ring 12 which extends into a strip 13 which is welded to the guide rod 4 and fastened to a further connecting terminal 14. In the embodiment described above, terminal 14 is the positive terminal and terminal 11 is grounded.

It is clear from the above description that the float 6 acts as a potentiometer slider for the winding 5.

The resistance of the winding 5 is a function of the position of the float 6 and thus provides an indication of the liquid level in the tank.

It will be appreciated that the use of a spiral member 10 for making the connection between the contact vane 7 and the connection terminal 11 on the output side makes it possible to eliminate angular guidance of the float 6 around the guide rod 4. A guide rod 4 of circular cross section can be used and the guide rod 4 of the float 6
It can be made to allow some rotational displacement in either direction around it.

A warning device may also be provided to illuminate a lamp (not shown) on the vehicle's instrument panel when the level of fuel in the tank reaches a predetermined minimum level. This warning device is made of a conductive material and has a hole 1 formed in the float 6 parallel to the axis of the float 6.
It is equipped with a rod 15 that can freely slide within the rod 6. The hole 16 is larger at the bottom and the float 6
A chamber 17 is formed which communicates with the inner periphery of the tube. Annular contacts 18 are provided on the upper side of chamber 17 and extend from these to strips 19 and are connected in a suitable manner, not shown, to strips 8 secured by screws 9. An enlarged head 20 is formed at the lower end of the conductive rod 15, and a conductive metal coil member 21 is provided within the chamber 17, with one end connected to the head 20 and the other end connected to the annular contact. child 18. Furthermore, the conductive rod 15 has a small protrusion 22 at its upper end. Float 6 is the first
When the fuel level is above the predetermined minimum amount at the position shown by the chain line in the figure, the protrusion 22
holds rod 15.

The warning device also has an annular contact plate 23 provided at the bottom 2 of the outer tube 1.

In the embodiment described above, the contact plate 23 is provided around a tube 24 made of conductive metal and in contact with the contact plate. The tube 24 is part of the guide rod 4 and forms the core of the guide rod 4, around which the guide rod 4 is made by extruding plastic material.

The tube 24 is used at the same time as the electrical conductor of the warning circuit, an annular contact 25 is fixed to the tube 24 at the top of the tube 24 and under the cover 3; Terminal 11, which is connected to the terminal 26 forming the positive terminal of the frame, is connected to the frame as already described.

However, other articulation means in the contact plate 23 can be used, for example by using the wall of the outer tube 1 as an electrical conductor.

The above-mentioned signal lamp is connected between the terminals 11 and 26, and when the fuel level falls below the above-mentioned minimum amount, the head 20 engages with the annular contact plate 23 and the signal lamp between the terminals 11 and 26 is connected. It is like closing a circuit and lighting a lamp. In this connection, it may be noted that the coil member 21 helps maintain the electrical connection between the head 20 of the rod 15 and the annular contact 18 in any case. In practice, some clearance is required between the rod 15 and the hole 16, requiring that the rod 15 be positioned precisely within the hole 16 and spaced apart from the annular contact 18. In this case, it is the coil member 21 that maintains the electrical connection.

It is also noted that since the contact plate 23 is disc-shaped, the angular displacement of the float 6 does not affect the operation of the warning circuit.

The fuel level warning value is determined by the length of the conductive rod 15, more precisely by the length of the portion of the rod that projects downward from the float 6.

The warning device described above has the advantage of operating without preventing the level gauge circuit from operating. In fact, when the fuel level falls below the warning position, the float 6 continues to descend unhindered, and the coil member 21 is simply compressed by the downward movement of the float 6. Another advantage is that no setting or installation adjustments are required.

Although a preferred embodiment of this invention has been described, it will be obvious that various modifications and changes can be made without departing from the scope of this invention.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a liquid level gauge according to the present invention;
FIG. 2 is a partial sectional view of the liquid level gauge shown in FIG. 1 rotated by 90 degrees, and FIG. 3 is a plan view of the level gauge shown in FIGS. 1 and 2. In the figure, 1: outer tube, 3: cover, 4: guide rod, 5: winding, 6: float, 7: contact vane,
8: strip, 10: spiral member, 11, 14: terminal,
15: rod, 16: hole, 19: strip, 20: head, 21: coil member, 22: protrusion, 23: contact plate, 24: tube, 25: contact, 26: terminal.

Claims (1)

[Scope of Claims] 1. A float formed with a central opening, a guide rod extending through the opening, and a winding formed by a conducting wire supported by the guide rod and extending over almost the entire length of the guide rod. , at least one electrically conductive vane supported in movable contact with the winding by the float, an outer tube forming a bottom part which is rotatably attached to the lower end of the guide rod and surrounding the float, the electrically conductive vane and the winding. An electrical connection part that connects one end to an output terminal, a contact supported by a float, a fixed contact provided at the bottom of the outer tube, and a closed circuit when the contacts come into contact with each other. The contact, supported by the float, is a conductive rod capable of sliding in a hole formed in the float, the axis of which is generally parallel to the axis of the guide rod, The rod has a retaining member at its upper end, and the fixed contact is in the form of a conductive surface located at the bottom of the outer tube. 2. The hole formed in the float has a narrow portion and an enlarged lower portion that is joined by a shoulder and opens into a central opening, and a conductive material is provided on the shoulder and the lower edge is the narrow portion of the hole. The liquid level gauge according to claim 1, which is aligned with the opening of the liquid level gauge. 3. The liquid level gauge according to claim 2, wherein a metal conducting wire connects the conductive rod to the conductive member. 4. The liquid level gauge according to claim 3, wherein the metal conductive wire has a spiral shape, and one end is connected to the lower end of the conductive rod and the other end is connected to the conductive member. 5. Claim 1, wherein the conductive surface is connected to a tubular member made of electrically conductive metal and forming the core of the guide rod, and the tubular member is connected to an output terminal.
The liquid level gauge according to any one of items 1 to 4. 6. The liquid level gauge according to claim 5, wherein the conductive surface is a perforated disk provided around the tubular member.