DE2210056B2 - Drive-over bridge for ramps - Google Patents

Description

45

The invention relates to bridges for ramps according to the preamble of claim 1.

In such bridge bridges, there are special requirements for moving the bridge plate and the extension Tax funds required. It is understood that a larger number of these control means the operation of the Override bridge made difficult, not only because of the susceptibility to failure of the control means, but also because of the risk of accidents should be kept as simple as possible.

In known bridge bridges (US-PS 33 88 413) is used to raise the bridge plate and to Extending the extension the pressure medium via a control valve for lifting the bridge plate Serving cylinder is supplied. When the bridge plate has reached its upper end position, the control valve conducts the pressure medium to the cylinder for extending the extension. Accordingly, to apply the Cylinder for the extension and the bridge plate a special control valve is required.

The invention is based on the object, the hydraulic drive for the bridge plate and the Extension of the crossing bridges mentioned at the beginning to train so that a separate control valve is superfluous and therefore an essential one Simplification of the hydraulic system is possible

This object is achieved by the in claim 1 characterized invention solved,

The invention is based on the knowledge that due to the larger opposing forces of the cylinder for Bridge plate initially remains at rest while the cylinder can be used for the extension. Has then the cylinder for the extension reaches its end position, so arises within the hydraulic System, a pressure increase that is sufficient to actuate the cylinder for the bridge tarpaulin Separate movements of the bridge plate and the extension can thus be carried out without control means.

This way of working is preferred for the Retraction of the extension provided a A modified arrangement is made for the extension, by only after a further proposal according to the invention when extending the extension whose cylinder is connected to the common pressure line, while the cylinder for the Bridge plate is locked

Further advantageous refinements of the invention are described in additional subclaims.

The invention is explained with reference to the drawing in which one is preferably used Embodiment of the invention shown is It shows

F i g. 1 a bridge for ramps in the side view and

F i g. 2 the hydraulic system for the drive-over bridge according to FIG. 1 in a schematic representation.

The bridge plate 1 of the drive-over bridge can be pivoted about a horizontal axis at its rear end; Below the bridge plate 1 in the ramp 2 there is one the size of the bridge plate 1 corresponding recess 3 into which the bridge plate 1 can be pivoted At the rear end of the Recess 3 is vlac bearing 4 for pivotable arrangement of the bridge plate 1.

The bridge plate 1 is designed as a hollow box girder and is used for movable storage a carriage 5 in the region of its front end; this carriage 5 is with an extension 6 for the Bridge plate 1 equipped. The extension 6 is used to bridge the gap between the unloading platform 7 and the bridge plate 1. Fig. 1 shows the extended position, so the operating position the extension 6, which can be retracted and extended with the aid of the cylinder 8 acted upon by pressure medium. in the In the retracted state of the extension 6, it is otherwise completely within the bridge plate 1.

Inside the recess 3 there is a bridge plate 1 below the bridge plate 1 which grips it from below Pressurized cylinder 9, with which the bridge plate 1 can be pivoted upwards Bridge plate 1 is balanced by weights not shown, but it still has a slight excess weight at its front end, in order to prevent the bridge plate 1 from sinking automatically achieve when the cylinder 9 is not under excess pressure or the outflow of the pressure medium readily can take place.

The cylinder 9 for the bridge plate 1 is a component a hydraulic unit 10 with an oil collecting tank 11 surrounding the cylinder 9, a Pressure pump 12 with electric drive motor 13. a

Control valve M with two push buttons t5, 16, one check valve 17 mechanically coupled therewith, two check valves 18, a pressure switch 19, one Overpressure valve 20 and various connecting lines.

The pressure relief valve 20 and the pressure switch 19 are only used for additional security and are available not directly related to the invention.

2 also shows that the Pressure pump 12 coming pressure line 21 leads to the control valve 14, the two connections 22,23 for the Has double-acting cylinder 8 for the extension 6 and also to one for the oil collecting container 11 leading return line 24 is connected from the connection 22 also a pressure line 25 goes to Cylinder 9 for the bridge plate 1 via the check valve 18.

The two are in the rest position according to FIG Connections 22, 23 blocked or not connected to lines 21, 24. This is also in the rest position Check valve 17 set to passage; It always locks when either the id or 16 is operated

Pressing the pushbutton 16 creates a flow in the sense of the illustration at 26; while the cylinder 8 executes a backward movement of the extension 6, but at the same time the cylinder 9 is acted upon, but since the carriage 5 offers only a slight resistance, initially only the carriage 5 moves; the bridge plate 1 remains at rest until the carriage 5 has reached its rear end position. When this end position is reached, the lifting movement of the bridge plate 1 begins. This is interrupted in the upper end position of the bridge plate 1 by a limit switch. The bridge plate 1 then sinks downwards due to its own selection.
This decrease can only occur when the pushbutton 16 is no longer pressed, the shut-off valve 17 also returning to the flow position shown in the drawing for the return flow of the pressure medium, while the symbol 27 corresponds to the symbol 27 when the pushbutton 16 (and also 15) is pressed the

Reflux is impossible

If the pushbutton 15 is pressed, the symbols 28 correspond to the carriage 5 with an extension 6 extended. An actuation of the cylinder 9 for

₍ The bridge plate 1 does not take place here; rather, its return is blocked again, whereby the bridge plate 1 is locked in the respective position.

The required movements of the bridge plate 1 and the associated extension 6 are thus in essentially possible through the two pushbuttons 15, 16. Basically these two are Drur, iasten 15, 16 die both command organs for the retraction and extension of the extension 6, however, with these two processes the movements of the bridge plate 1 coupled sensibly, assuming the fact that at non-bridged pushbuttons 15,16 the bridge plate 1 moves downwards automatically. The retraction of the extension 6 is also only advantageous together with a lifting of the bridge plate 1 can be carried out; this coupling through the common connection of the Pressure line 21 for the cylinders 8 and 9 at 22 leads to a considerable simplification of the hydraulic Systems.

1 sheet of drawings

Claims (5)

Claims; 1. Bridge bridge for ramps with one at the Ramp around a horizontal axis pivotable bridge plate and one at the free end of the Bridge plate retractable and extendable extension to rest on the 501 unloading platform, the bridge plate and the extension being pressurized by pressure medium Cylinders are movable, which can be connected to a common pressure line, characterized in that that the two cylinders (8, 9) are connected to the pressure line (21) in such a way that to move the extension (6) both cylinders (8, 9) can be pressurized, the cylinder (9) for however, the bridge plate (1) only becomes effective when the cylinder (8) for the extension (6) is its Has taken its end position 2. Overhead bridge according to claim 1, characterized characterized that for the retraction and extension of the A control valve (14) is provided for extension (6) is, with which a shut-off valve (17) is coupled in the Way that in all active positions of the control valve (14) the return flow for the cylinder (9) of the Bridge plate (1) shut off, but the return flow is open when the control valve is not actuated 3. Transfer bridge according to claim 1, characterized in that the mechanical resistances for the cylinders (8, 9) and / or the effective cylinder surfaces are different. 4. Transfer bridge according to claim 1, characterized in that the cylinder (9) for the Bridge plate (1) only when retracting the extension (6) together with the cylinder (8) for this extension (b) is connected to the common pressure line (21), st 5. bridge according to claim 1 and 2, characterized in that when extending the Extension (6) only whose cylinder (8) is connected to the common pressure line (21), while the cylinder (9) for the bridge plate (1) is locked.