JPS6084403A - Pressure cylinder apparatus operable by liquid pressure - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The invention relates to a hydraulically operable pressure cylinder arrangement according to the preamble of the patent claims.

In pressure cylinder arrangements of the kind described above, as a result of pressure medium losses, but also for other reasons, there is no longer a synchronous movement of two or more pistons in the pressure cylinder, so that the pistons Often they are no longer located at the same height. This necessarily affects the position of the part to be raised or lowered by the piston of the pressure cylinder.

If the piston rods of these pressure pistons are connected, for example, to the frame of a vehicle seat, a tilting of the seat occurs;
It is important to avoid this.

OBJECTS OF THE INVENTION It is an object of the present invention to improve a hydraulically operable pressure cylinder device of the above-mentioned type, which makes it possible to adjust the pistons in the case of differences in their height positions. The purpose is to ensure that the piston is again located in the same horizontal plane, thereby avoiding tilting of the vehicle seat.

Means for achieving the object This object is achieved in a pressure cylinder device according to the preamble of the claims, in which the feed line of the pump can be connected to the connecting line via an overflow valve. is solved by opening the flow path of the pressure medium from the feed line to the connecting line when a predetermined maximum pressure is reached.

By means of this measure according to the invention, the pistons can be readjusted so that they all lie in the same plane in a device filled with pressure medium.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the pressure cylinder device according to the invention is schematically shown in the drawing in connection with a lifting device for a motor vehicle seat.

It is clear that the inventive concept is of course in no way limited to this.

At 1 a seat frame is shown which is raised or lowered by means of a hydraulically operable pressure cylinder device. A total of four pressure cylinders are provided for this purpose, each of which acts on the seat frame 1 in the area of a corner point. The drawing shows only two of these four pressure cylinders, namely pressure cylinders 2 and 3, in which pistons 4 or 5 are slidingly guided and whose piston rods 6 or 7 is connected to the seat frame 1 in a suitable manner.

The pistons 4, 5 move the pressure cylinders 2, 3 into the upper chamber 8 or l.
It is divided into O and lower chamber 9 or 11. pressure cylinder 2
The upper chamber 8 is connected to the adjacent pressure cylinder 3 via a connecting line 12.
It can be connected to the lower chamber 11 of. This naturally also applies in the case of two or more pressure cylinders connected in series in this way.

Furthermore, a pump 14 which can be operated by hand via a lever 13
This pump connects the lower chamber 9 of the pressure cylinder 2 or the upper chamber 10 of the adjacent pressure cylinder 3 to a pipe line 15 or 16, respectively, and when raising the seat frame 1, the pipe line 15 is a feed pipe, while pipe 16
is in this case the return line of pump I4.

The line system is connected to a pressure medium reservoir 17, in which a gas cushion 18 is advantageously provided.

The feed line 15 of Pump 4 is connected to the connecting line 12 via an overflow valve 19, and when the overflow valve reaches a predetermined maximum pressure, the feed line 15 is connected to the connecting line 12. The operation of the pressure cylinder device between the pressure medium flow path is as follows.

It is assumed that all parts of the device occupy the positions shown in the drawings. Now, the seat frame l, so again my own Iv.
If you are trying to raise the I-car seat, pump 14.
The lever 13 is swung back and forth, so that pressure medium flows into the lower chamber 9 of the pressure cylinder 2 via the feed line 15 and moves the piston 4 upwards. As a result, the pressure medium present in the upper chamber 8 is forced into the lower chamber 11 of the adjacent pressure cylinder 3 via the connecting line 12, so that the piston 5 is thus forced through the piston rod 7 of this piston. The seat frame 1 is also raised. The pressure medium returns again to the pump 14 via the return line 16. The upward movement takes place synchronously so that both pistons 4 and 5 are always located in the same horizontal plane.

Now, if it is desired to lower the seat frame 1 and therefore the vehicle seat again, the pump 14 is switched λ - its side 1
As a result of the T movement, the feed line 1 from the lower chamber 9 of the pressure cylinder 2 now acts as a return line.
Since the pressure medium is discharged via the piston 4
descends.

However, the lower part of the pressure cylinder 3 3. Pressure medium is also discharged from ++ into the upper chamber 8 via the connecting line 12. Pressure medium is then forced into the upper chamber IO of the pressure cylinder 3 via the return line 16, which now acts as a feed line. Since pumps of this type are well known, individual details, in particular the elements necessary for switching, will not be discussed in detail.

Now, assume that the lower chamber II of the pressure cylinder 3 is not airtight, so that the piston 5 descends, and as a result, the seat tilts. In order to avoid this operational width damage, the pump 14
is operated until the piston 4 of the pressure cylinder 2 hits the upper end face of the cylinder housing and thus reaches top dead center. By further operating the pump 14 a maximum pressure is obtained in the line 15 and also in the lower chamber 9, the overflow valve 19 is opened and the pressure medium enters the lower chamber 11 of the pressure cylinder 3 via the connecting line 12. 2, where the piston 5 likewise reaches its top dead center position. As a result, both pistons 4, 5 are again located in the same plane.

Proceed in the manner described above until all pistons of the pressure cylinder arrangement reach the top dead center position and are located in the same plane. Pressure medium losses are compensated by the pressure medium present in storage vessel 17.

[Brief explanation of the drawing]

The drawing is a schematic illustration of a pressure cylinder device according to the invention. 12... Connecting pipe line, 14... Pump, 15... Feed line, 19... Overflow valve patent applicant Günther Lemmelpach same Gunther Friedrich Rentrowpuschmie 1

Claims (1)

[Claims] Each pressure cylinder of a plurality of pressure cylinders connected in series has a piston that acts on the motor vehicle seat, this piston dividing the pressure cylinder into a lower chamber and an upper chamber, the upper chamber of one pressure cylinder being connected to the pressure of the adjacent pressure cylinder. A pump, preferably manually operable, is provided, which can be connected to the lower chamber of the cylinder via a connecting line and which can be connected to the lower chamber of one pressure cylinder or the upper chamber of an adjacent pressure cylinder through a line in each case. When the seat is raised, the pipe connected to the lower chamber is the feed pipe, and when the seat is raised, the pipe connected to the upper chamber is the return pipe of the pump. In a hydraulically operable pressure cylinder arrangement, in particular for raising and lowering a motor vehicle seat, in which the line system is connected to a pressure medium storage vessel, the feed line (15) of the pump (14) is Connecting pipe (1) via overflow valve (19)
2), and when this overflow valve reaches a predetermined maximum pressure, the feed pipe (15) can be connected to the connecting pipe (12).
) A hydraulically operable pressure cylinder device, characterized in that it opens a flow path for pressure medium to