DE658135C - Device for lifting loading bridges - Google Patents

Description

Which used to be widely used for lifting loading bridges, especially on trucks hydraulic tipping devices with hand pumps (hand tippers) have been pushed back very strongly by the motor pumps, because the hand pump work is no longer fully up to the increased performance in tipping truck operation.

When operating the hand pump, the operating team can perform the quick succession You can no longer cope with the tilting of a work shift without excessive fatigue, because the one for dining is a multi-flask hydraulic press previously in use

ig single-stage hand pumps in labor fluctuate very much. You demand adequate lifting work when starting tipping, which decreases with the increasing tilt angle and in the same ratio

ao increasing press load gradually reduced when using the next one smaller piston of the press but suddenly increases, which occurs with every piston change the press repeatedly until its weakest piston starts to lift. The result of it Repeated, sudden, sharp increases during the pumping work work on the pump just as often causes an increased onset of the Forces of the operating team, which not only perceived as unpleasant top performance is, but also fatigued to a great extent. This multiple peak performance can be achieved with. Motor pumps are disregarded; In the case of hand pumps, it causes very irregular pump work, which affects the overall performance adversely affected and thus also significantly impaired the duration of a tilt.

The invention relates to a device for lifting loading bridges, in particular on trucks, powered by a hand pump. Tilting device, which is designed so that it has the best possible efficiency in terms of effort and has an even work performance during the entire tipping period and thereby promotes the hand pump operation for hydraulic tilting devices in such a way that that it meets all requirements as a high-performance hand tipper.

The invention is essentially characterized in that the stages of a multi-stage Piston press to the stages of a hand pump with several piston stages in such a relationship that the manual pump work on the pump lever remains approximately the same. The even Work on the hand pump can be done with the previously used single-stage, hand pump working on a multi-stage piston press.

In the drawing, the subject matter of the invention is shown, for example, in one embodiment. Fig. Ι shows a schematic diagram of the overall arrangement and Fig. 2 shows a vertical section through the new hand pump. 3; 3 The multi-piston press with 2, B. three KolMij a, a ¹ , « ² , which tilts the bridge b backwards and to both sides in a known manner (three-way tipper), is through the pressure and return line w £ with the hand pump < e in hydraulic connection. The tipping device valve equipment required for raising and lowering the loading bridge and valve equipment does not differ in any way from the equipment previously used.

The hand pump container e (Fig. 2) forms an annular and bottom chamber on the outside, which is connected to the pressure medium, e.g. B. OIL is full. The full cylinder .g · for receiving the pump pistons, which are moved by the rocker arm h , is located within this pressure medium chamber.

The pump pistons are multi-stage, in accordance with the multi-piston press a, a \, Φ as three-stage ^{pistons, /, Z 1} , / ² , the cross-sections of these stages being approximately the same as the cross-sections of the pistons a, a ¹ , a ^{2 of} the press match proportionally. At the ; At the end of each cylinder stage there is a suction valve k, k ¹ , k-, which release or shut off the pressure medium flow. The upper suction valves k, k ¹ can with the help of a suitable device, for. B. by means of axes of rotation / and. on these attached grippers m, are switched off by hand.

The mode of operation of this hand pump with multi-stage pistons is as follows:

At the beginning of the tilting, the chamber / is completely filled with the pressure medium, for example oil. With this pressure medium level, the pump works with the piston stages with the largest cross-section. I corresponds to the largest piston λ of the press. When this has reached its final stroke position, the oil level in the chamber / has sunk so far that it releases the uppermost suction valve k. This automatically switches off the piston stages /, and the weaker middle piston stages V- of the hand pump now work, corresponding to the middle piston ß ^{1 of} the press. As soon as this reaches its final stroke position and the third piston ä ^{2 of} the press starts to stroke, the oil level has also sunk below the suction valves k ¹ , whereby the middle piston stages V of the hand pump are switched off and the weakest piston stages i ^{2 of} the hand pump start to work, in accordance with the weakest piston a ^{2 of} the press. The new hand pump automatically changes the gear ratio of the pump in relation to the press when the piston is changed in the press. Through this . is without any intervention of the operation - '* m _s annschaft, despite strong pressure increase ^ b ^ ün piston changing the press, penleistung a r while S © whole Kippdauer approximately the same pump ■ or made a consistent effort of the operating team that no longer prematurely tired.

The surfaces of the pump piston stages i, V, i ^s do not need exactly the surfaces of the plungers α, ϋλ, α? but are kept in such a way that, taking into account the press load, which is steadily decreasing when tilting, and the hydraulic pressure that changes in jerks, a balanced workload must be applied to the pump lever.

In addition to the automatic change in the transmission ratio between the pump and press caused by the drop in the oil level, the transmission ratio can also be controlled mechanically with the aid of the spindles / moving grippers tn. This mechanical control can be desirable, for example, when the power to be applied to the hand pump is too great in relation to the variable tipping load and the operating team is very strenuous. In such cases, either the upper suction valves / e or the middle suction valves k ^{1 can be} switched off by means of the spindles Z, so that the hand pump works with a piston of smaller cross section on a piston of larger cross section of the press. The effort required for the pump is reduced while increasing the working time on the pump.

The hand pump with multi-stage piston training can optionally also with a hydraulic single piston press can be used:. den, the pistons of the hand pump either come into effect one after the other or one or more piston stages of the Hand pump can be switched off mechanically in the manner described above.

The structural design of the hand pump is very simple; the fitting, the stepped piston and the placement of the suction valves are no problem. The establishment mechanical shutdown of the suction valves can also be kept simple. The advantages of the new hand pump: even output of the pump, even, The least possible strain on the operating team, automatic and mechanically effective regulation of the transmission ratio, as well as the simple design of the hand pump, result in maximum performance for hand pump operation, which will become competitive again.

Claims (2)

Patent claims: ι. Device for lifting loading bridges and the like, in particular on trucks, by means of a tilting device fed by a hand pump, characterized in that the stages of a multi-stage piston press (α, β ¹ , α ² ) to the stages of a hand pump with several Piston stages (i, i ¹ , i ² ) are in such a ratio that the manual pump work on the pump lever (A) remains approximately the same. 2. Device according to claim i, characterized in that the pressure medium container (/) of the hand pump at the foot of the cylinder stages is provided with suction valves (k, k ¹ , k ² ) which gradually switch off the upper piston stages when the pressure medium level drops. 1 sheet of drawings