DE1240743B - Hydraulic piston drive with telescopic piston - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

F15b

German class: 60 - 30

Number: 1240743

File number: T 280031 a / 60

Filing date: February 17, 1965

Open date: May 18, 1967

The invention relates to a hydraulic piston drive, which consists of a pressurizable Cylinder and at least two telescopic pistons which can be displaced one inside the other, the outer piston is displaceable in the cylinder and separates an annular chamber from its interior and one with this annular chamber has a cavity connected to it, which receives the inner piston, and the under The pressurizable cylinder chamber and the cavity are connected via a valve, which when approached the piston is forcibly opened to the retracted position by a control member.

The inner piston can, if more than two telescopic pistons are provided, in turn one Have a cavity that accommodates another piston, etc. In such drives are during of lifting and lowering, all pistons are always in motion, with different, with constant pressure medium supply or discharge, however, uniform speeds over the entire stroke. They are therefore referred to as synchronous drives.

In the event of a sealing fault between a piston and the cavity surrounding it, as well as as a result Due to the compressibility of the oil, it can happen that, after a certain operating time, not all pistons reach their end positions when lowering. It is already known to remedy this by using the connects the pressurizable cylinder chamber and the cavity of the outer piston via a valve, which is inevitably opened by a control element when the pistons approach the retracted position is proceeding accordingly with valves that connect when approaching the retracted position Establish between adjacent chambers, which are separated by further pistons are separated.

The valves mentioned fulfill their purpose fully, but have the consequence that in the very first Phase of the stroke movement in which the valves are still all open affects the synchronization will. Because synchronism presupposes that the mentioned chambers are all during the raising and lowering are separated from each other.

The invention seeks to remedy this deficiency. It ensures that the valves mentioned when starting all closed before the pistons begin to move and that they are all closed Do not open until the pistons have retracted and come to a standstill.

For this purpose, if it is a drive with two pistons, the control member of the hydraulic piston drive
with telescopic piston

Applicant:

Toussaint & Hess

hydraulic hoist factory G. m. b. H.,

Düsseldorf, Völklinger Str., 48

Named as inventor:
Hans Becker,
Mathieu Toussaint, Düsseldorf

«Ο in this case single valve mounted axially movable against spring force and is subject to the spring force opposite action of the pressure in the cylinder chamber, whereby when this pressure rises the valve closes.

If the cylinder chamber is pressurized, then at a certain pressure, which is not yet sufficient to raise the outer piston, the control member is displaced and thus releases the valve controlled by it, so that it goes into the closed position. Only when the pressure in the cylinder chamber then reaches an even higher value do the pistons start moving, which is uniform from the first moment on.
Correspondingly, if the drive contains three or more pistons, the additional valves then required can be operated. Each such valve can in turn be assigned a control member which is mounted axially movable against spring force and under which the pressure in the relevant piston chamber acts opposite to the spring force.

However, the preferred embodiment of the invention provides only one for the case of more than two pistons The only one that can move against spring force and is under the action of pressure in the cylinder chamber standing control member in front. In this preferred embodiment, the control elements for the remaining valves are used of the invention, the spring-loaded valve body of the next lower valve.

The drawing illustrates an embodiment in three longitudinal sections through one according to the invention designed piston drive. It shows

709 580/163

Claims (1)

F i g. 1 the drive in the retracted position for parts in the position according to FIG. 1. Under the effect pressureless cylinder chamber, the spring 45, the control piston 44 is in the raised F i g. 2 the drive before starting when the ner position and holds the shaft 36 the Pressure in the cylinder chamber a certain valve body 35 against the spring 38 in the open position. Has exceeded the value, and 5 Correspondingly, the stem 37 holds this valve Fig. 3 shows the drive during lifting or the valve body 40 via the shaft 41 against the Wenkens; Spring 42 in the open position. So are at rest F i g. 4 finally shows a modification. all chambers connected to each other. The drive shown consists of a cylinder. If the pistons are to be extended, it will be the 10 with end wall 11 and a channel 12, through io via the channel 12 pressure on the cylinder chamber given the cylinder chamber 13 to a 13 not shown. The spring 45 is biased so that the hydraulic pressure source can be connected. in the chamber 13 increasing pressure the control In the cylinder 10, a hollow piston 14 is displaceable, piston 44 is pushed back before it reaches the amount which is closed at the bottom by an end wall 15, in which he has the piston 14 and thus all the rest on which a piston lifts up on the inner wall of the cylinder 10 with the load. First, therefore, the sealed sliding flange 16 is formed. The position shown in Fig. 2, in which the control against the wall 10 recessed cylinder wall 14 piston 44 has receded and the valve body forms with this an annular space 17, which releases the top through 35 and 40, so that they are under the action a flange 18 of their springs 38 and 42 formed on the cylinder wall go into the closed position. the is complete with seal. 20 chambers, none for reasons of synchronism Another hollow piston 19 is located in the piston 14 slidable, the end wall 20 of which in turn is separated from each other before the piston movement beDichtung provided flange 21 has, which at the inginnt. inner wall of the hollow piston 14 slides. The piston 14 has the pressure in the cylinder chamber 13 19 and 19 together form an annular space 22 which reaches a value which is necessary to overcome the load If piston weights are necessary at the top due to a flange arranged on the piston 14, all three are seated 23 is completed with a seal. Finally, in the piston is simultaneous and with staggered Geschwin-Hohlkolbenl9 a piston 24 displaceable, which moves with speed and pass through the this forms an annular space 25, which at the top by position according to FIG. 3, while the control piston 44 a sealed flange 26 of the KoI-30 remains in the displaced position. When lowering bens 19 is complete. At the lower edge, the position according to FIG. 3 is again passed through Piston 24 has a flange 27 which acts as a stop to and finally returns to the position according to FIG. 2 stroke limitation when extending. is enough without the valves 34 and 39 Synchronization is obtained by opening the ring. Only when the pressure in the cylinder Space 17 is lowered even further through openings 28 of the piston 14 with the chamber 13, the sen interior 29 is connected, in which the KoI control piston 44 under the action of the spring 45 and ben 19 is movable, and that accordingly opens the valves 34 and 39. It is natural to do so Openings 30 of the annular space 22 with the interior space necessary to dimension the springs 38 and 42 so 31 of the piston 19 is connected, in which the fact that they are transferred by the counteraction of the spring 45 Piston 24 moves. 4 ° is essential for synchronism. furthermore that normally between all of these the control member need not be in the form of a Chambers otherwise no connections exist. To have control piston, as shown in Fig. 1 to 3 Is on the undersides of the piston end walls 15 and draws. Rather, the piston can also according to 20 stops 32 are attached to prevent F i g. 4 by a clamped in the end wall 11 the end faces lie on top of each other, so that 45 membrane 47 are replaced, the one in the middle the effective printing areas remain unaffected. Washer 48 carries, under the action of a compression spring In the end wall 15 there is a general reference number 34 and with the disk 48 in the same way Drawn valve arranged, which acts from a valve on the valve stem 36 like the control piston body 35 and two shafts 36 and 37. On 44 according to FIG. 1 to 3. a pretensioned screw 50 acts on the valve body 35 benf eder 38. In the open position, the Ven- patent claims:
til 34 the cylinder chamber 13 with the interior 29 of the piston 14. Correspondingly, the first contains hydraulic piston drive, consisting of End wall 20 of the piston 19 a generally 39 with a pressurizable cylinder and min- designated valve, which consists of a valve body 40 55 at least two telescopic telescopic and a shaft 41. The valve body 40 piston, with the outer piston in the cylinder is under the effect of a pre-tensioned screw and is displaceable from its interior benfeder 42. In the open position, the valve connects the ring chamber and separates one with this ring til 39 has the interior 29 of the piston 14 with the in-chamber connected cavity, which the internal interior space 31 of the piston 19. 60 neren piston receives, and the lower In a bore 43 of the end wall 11 is pressurizable cylinder chamber in alignment and the hollow are connected to the centrally arranged valves 34 and 39 space via a valve, which at a control piston 44 displaceable, which under the we- approach of the piston to the retracted position kung of a preloaded spring 45 is available. The well is positively opened by a control element tion 43 is to the outside by a plate 46, characterized in that the closed. Control element (44, 47) against spring force (45, 48) Are the pistons retracted and is the axially movable bearing and under which the Cylinder chamber 13 depressurized, so there are the opposite action of the spring force