FR2548288A1 - DEVICE FOR AUTOMATICALLY INVERTING THE POWER SUPPLY OF A HYDRAULIC DOUBLE-EFFECT CYLINDER FROM SINGLE OR DOUBLE-EFFECT CONTROL - Google Patents

Abstract

THE INVENTION RELATES TO A DEVICE ALLOWING THE AUTOMATIC REVERSAL OF THE POWER SUPPLY OF A DOUBLE HYDRAULIC JACK FROM A SINGLE OR DOUBLE ACTING CONTROL. IN ACCORDANCE WITH THE INVENTION, THE INFORMATION THAT TRIGGES THE REVERSE IS TAKEN FROM THE DRAIN CHAMBER OF THE CYLINDER. A MEAN PROBE 11-12-12A-15 STATES THE FLOW STATE AND THE STATE OF NO FLOW OF THE CHAMBER IN DRAINING OF THE CYLINDER AND STARTS THE REVERSE FOR A ZERO FLOW. A MEANS OF DELAY 5-6-9-10 DELAYS THE STATE OF THE FLOW OF THE DRAINING CHAMBER TO ALLOW THE CYLINDER TO START. THE INVENTION APPLIES, IN A GENERAL WAY, TO THE AUTOMATIC REVERSAL OF THE POWER SUPPLY OF A DOUBLE HYDRAULIC JACK.

Description

The present invention relates to a device for reversing

  automatic feeding of a hydraulic double acting cylinder from a control

single or double effect.

  In a double-acting cylinder when a fluid under pressure is admitted into a chamber, the fluid contained in the other chamber is expelled towards the reservoir As soon as an internal or external stop stops the movement of the

  cylinder, the emptying flow becomes zero.

  According to the invention, the information that triggers the inversion is advantageously taken from the

chamber emptying the cylinder.

  A feeler means detects the flow status of the

  cylinder emptying chamber as the state of absence of 15 flow of this room.

  As long as there is flow from said chamber, the inversion is not controlled As soon as the flow stops, the inversion is controlled and stored until the end of the cycle. From a stable position, the cylinder performs an automatic return and return cycle According to its direction of connection to the device according to the invention, the

  cylinder has its stable position rod exit or stem retracted and the automatic reversal takes place as soon as it stops; either in internal abutment or in external abutment.

  The flow sensing means is controlled by a delay which authorizes or does not authorize the piloting

an inverter distributor.

  Other features and benefits of the

  present invention will emerge from the description which will

  follow made with reference to the accompanying drawings, in which: Figure 1 is a diagram of a device according to the invention, at rest;

  Figures 2 to 4 are diagrams showing this same device in other phases of operation.

  In general, the device according to the invention comprises a probe means (11-12-12 A-15) which detects the state of flow and the state of no flow of the chamber emptying the cylinder; delay means (56-9-10) which delays the observation of this bit rate; and

  a pilot-operated check valve (1-2-3-4-22) which locks in the extended rod position the double-acting cylinder considered.

  Figure 1 shows the device at rest, that is to say that its orifices P (pressure) and V {(emptying can be closed or open to the tank and by the external control valve (not shown). connected to ports A and B is locked out stem by the pilot operated check valve (1-2-3-4-22) _ automatic power supply double effect of the device is

  effective at passages A 1 and BI.

  In general, the supply available on 15 at A 1 and B 1 is a first time when the pressurized fluid leaves Bi, while A 1 is at the emptying and a second reverse time, that is to say say that the fluid comes out

  At 1, while Bl is at the drain.

  When the fluid is admitted under: pressure P, the orifice V being at the drain (FIG. 1), the fluid actuates a piston 5 of the delay (5-6-9-1) 0 delimiting two chambers: a chamber 10 which i with the passage Bl and a chamber 9 which communicates with the passage A 1, through a calibrated orifice 8. 25 In its normal rest position the piston 5 is rapeâé by a spring 6 and closes a passage 7 The time required to empty the chamber 9 through the calibrated orifice 8 determines the delay which makes it possible to wait for the movement of the cylinder to be started before ascertaining the state of the emptying flow, that is to say to say close

  passages 12 and 12 A before opening passage 7.

  FIG. 2 shows the actuator moving Ra the retracted rod direction. The fluid arriving from P fills the annular section of the cylinder and actuates a pilot 1 which opens a valve 3 of the pilot check valve (1-2-3-422). The fluid contained in the bottom section of the cylinder is discharged to a space 13 where it is required, to pass to a passage 14, to move a slide (11) of the flow sensor (11-12-12 A -15), which closes the passages 12 and 12A The time required to start the cylinder, that is to say since the admission of the fluid until the closing of the passages 12 and 12 A, is shorter than the displacement of the piston (5) of the delay, until the opening of the passage 7. As soon as the movement of the cylinder stops by the internal stop or an external stop (Figure 3), the emptying flow ceases in the space 13 and the drawer (11) re10 comes to its initial position recalled by a spring (15), which opens the passages 12 and 12 A and allows the fluid always has P-urged to push, firstly, a drain valve 16 and, in a second step, a

inversion drawer 17.

  The fluid always admitted P (Figure 4) flows through a space 18 and will supply the full section of the cylinder through a valve 19 and the valve 3 A valve 20 opens to let the fluid in a chamber 21 A valve 27 emp Oche the fluid admitted in the chamber 21 to drain by 12, 12 A and 7 (the passage 7 is closed

not immediately).

  This arrangement with a valve (20) and a valve (27) constitutes a storage of the position of the slide (17) which is held by the pilot valve (16) as long as there is pressure at (P) through the calibrated orifice 8, the fluid pushes the piston 5 of the delay in its initial position The annular chamber of the jack, the chamber 10 and a chamber 22 of the piloted check valve drain through a space 23 in communication with the orifice V. When the pressure in P is cut, the valve 20 closes and the fluid contained in the chamber 21 is evacuated by a calibrated orifice 24 thus allowing a volume transfer The pilot 16, under the action of a spring

  , and the slide 17, under the action of a spring 26, 35 can resume their initial position.

  It is understood that the present invention has been described and shown only as a preferred example and that it will be possible to provide equivalences in its constituent elements, without, however, out

of the scope of the invention.

  Thus, from the passages A 1 and B 1, 5 it is possible to perform different cylinder and check valve connection diagrams without changing the operation of the device, that is to say: lock the section annular cylinder and leave free the full section of the cylinder; 10 lock both sections; reverse the direction of movement of the cycle by reversing the cylinder etc.

Claims (4)

  1 Device allowing an automatic reversal by cycle of a double-acting cylinder, characterized in that the information that triggers the inversion is taken on the chamber emptying the cylinder. 2 Device according to Claim 1, characterized in that a feeler means (11-1212 A-15) detects   the state of flow and the state of no flow of the chamber emptying the cylinder and triggers the inversion for a zero flow.   3 Device according to claim 2, characterized in that a delay means (5-6-9-10) delays   the flow rate of the emptying chamber to allow the cylinder to start.   4 Device according to any one of claims 1 to 3, characterized in that it comprises a   reversing slide (17) held in the pushed position by a drain valve (16) which position is memorized   by a valve (20) and a valve (27) as long as there is pressure at (2 P).