FR2705656A1 - Hydraulic connection for controlling hydraulic motors associated with a friction winch upstream of which an accumulation drum is installed. - Google Patents

Abstract

In said connection, a distributor (11), the control of which can be reversed as a function of the winding direction, is provided in hydraulic conduits (9, 10) leading to the hydraulic motor (7) of an accumulation drum (2), between the connections (19, 19 ') of a transverse conduit (16) with the conduits (9, 10) leading to a hydraulic pump (8), and a pressure relief valve (25) integrated in a conduit hydraulic (23) leading to the hydraulic motor (7) of said drum (2). Said limiter is produced in the form of a reduction / braking valve (25) which can be influenced by the pressure prevailing in a hydraulic conduit (14) leading to the hydraulic motor (5) of a friction winch (1).

Description

HYDRAULIC CONNECTION FOR MOTOR CONTROL

  HYDRAULICS ASSOCIATED WITH A FRICTION WINCH UPSTREAM

  AN ACCUMULATION DRUM IS INSTALLED

  The present invention relates to a hy-

  system for controlling associated hydraulic motors

  to a friction winch upstream of which a storage drum

  tion is installed, said motors being connected to a hydraulic pump by means of hydraulic conduits, connection in which a respective pressure relief valve is integrated in one considered of the hydraulic conduits connecting the hydraulic pump to the hydraulic motors, and in a

  transverse duct connecting the hydraulic conduits connected

hydraulic pump dice.

  When laying cables in tu-

  cables or channels extending underground, the cables are unwound from drums using friction winches designated by "capstans", then are respectively introduced into the

  tubular pipes or in canals. The cables pre-

  frequently feel a length of several hundred

  meters. The installation path is dependent on the circumstances

  constants pre-established locally, often describing curves. To introduce a cable into a tube, a steel rope is first unwound from an accumulation roller, then inserted into the tube via the friction winch. A plug, to which the steel wire is subjected, is conveyed for this purpose through the tube, by means of compressed air. In the sequence, the cable to be laid is attached to the free end of the steel rope. The cable can now be introduced into the tube using the friction winch. The friction winch and the accumulation drum are

  both trained. As a rule, this training

  ment is ensured by hydraulic motors. These latter

  are supplied with hydraulic fluid by a hydraulic pump

  than variable displacement. So far, hy-

  hydraulics were connected to each other in a conventional parallel connection. The winding diameter decreases in

  permanence as the steel wire is deflected

  thimble of the accumulation drum. This results, respectively,

  that the wire feed speed decreases or that the angular speed

  the area of the accumulation drum increases at a speed of

  constant unwinding. This translates into higher demand

  re of the drum motor in hydraulic fluid, i.e.

  by an increase in the absorption volume of the drum motor

  bour. This implies that the capstan motor does not have

  sufficient hydraulic fluid, and that the

  seems the system is slowing down. As a result, the time required for the passage of a cable is significantly extended. This is

  why, in order to get around the difficulty, it is necessary

  Be sure to use a capstan motor with variable absorption volume. As already mentioned above, a cap is all

  first set in motion in the tube, by means of compressed air

  me. If this plug gets stuck, the fry winch

  no longer undergoes any resistance and the steel rope

  tine on the friction winch drum. However, the tam-

  bour of accumulation tends to continue the unwinding of the

made of its mass of inertia.

  To keep the steel wire bandaged during the pro-

  unwinding, the hydraulic motor of the storage drum

  mulation is requested by a braking torque. In the mo-

  of known connection, one operates with a torque

  swimming fixedly set. This couple is pre-established by the

  through a pressure limiter and is fully imposed on the drum motor, regardless of the diameter. The total braking power must then be fully

converted to heat.

  Another disadvantage is that the cost

  The set brake shoe must also be used to stop the accumulation drum. Consequently, it must be oversized since it must guarantee a safe shutdown of the storage drum, also during the sudden immobilization of the cable introduction (wedging of the plug) and, by elsewhere, when said plug

  comes out at the end of the tube (removal of tire pressure

  matic). Because the braking torque, intended to bandage

  the rope between the friction winch and the accumulator drum

  lation, remains equal during the entire unwinding process, also when the winding diameter changes, and the fact that, on the other hand however, the unwinding force varies with the winding diameter, this results in variations

  in the tension of the rope. Indeed, the latter is direct-

  proportional to the variation in diameter. The rope tension is low when the diameter is large, and strong

when the diameter is small.

  On the basis of these considerations, the invention has for

  purpose of providing a hydraulic connection designed to com-

  hydraulic motors associated with a hoist

  upstream of which an accumulation drum is installed, this connection guaranteeing automatic coordination of

  relationships between couples and pressures in different

annuities conditions of service.

  According to the invention, this object is achieved by

  the fact that a distributor, whose order can be reversed-

  seed according to the winding direction, is provided in the hydraulic conduits reaching the hydraulic motor of the

  accumulation drum, between the connections of the trans-

  versal with the hydraulic lines leading to the hy-

  hydraulic, and the pressure limiter integrated in the duct

  hydraulic drive to the hydraulic motor of the accumulator drum

  lation; and by the fact that the pressure relief valve is real

  read in the form of a reduction / braking valve, which can

  be influenced by the pressure in the hy-

  hydraulics leading to the hydraulic motor of the friction winch.

  The essential aspect of the invention resides in the me-

  consisting of integrating, in the hydraulic conduits leading to the hydraulic motor of the accumulation drum, a reduction / braking valve and a distributor, the

  command can be reversed depending on the winding direction

  lement. The reduction / braking valve can be influenced by the pressure prevailing in the hydraulic line leading

  to the hydraulic motor of the friction winch.

  The reduction valve / brake valve control fitting

  Swimming is then connected, by means of a control conduit, to the hydraulic conduit leading to the hydraulic motor of the friction winch. The distributor is preferably made up of

a 4/2 type distributor.

  Advantageously, the distribution control fittings

  are subject to the influence of the pressure prevailing in the hydraulic conduits leading to the hydraulic motor of the

accumulation drum.

  When winding the steel wire, respectively when introducing a cable, the connection acts like the parallel connection known up to now. At the stadium

  of the wire rope reel, the distributor switches all

  times automatically, so that the hydraulic motor

  that the accumulation drum additionally fulfills the function of a pump. Whereas, in the established connection

  until now, the reeling is slowing more and more

  te the decrease in the winding diameter of the drum

  cumulation, and following the greater correlative demand of the drum motor in hydraulic fluid, this slowdown

  is deleted in the connection according to the invention. Of-

  now during the reeling process (operation

  by generator), the drum motor supplies additional-

  the hydraulic circuit in hydraulic fluid. The mo-

  drum drum rotates faster and faster as

  sure that the winding diameter decreases, so that the unwinding can even take place with increased speed. A constant power motor can now be used as a

  as the capstan motor for the entire diametral range.

  During the unwinding, the drum motor develops a pressure representing the load pressure. The connection according to the invention has the effect that the pump pressure and the charge pressure counterbalance each other. The drum motor then operates by opposing the pumping pressure and the reduction / braking valve. This reduction / braking valve must only remove the pressure difference between the charge pressure and the pumping pressure. The difference between the charge pressure and the pumping pressure, dictated by the structural arrangement, results in the desired braking torque respectively

  imposed on the storage drum or the drum motor.

  Whereas, in the connection concretized until pre-

  felt, the braking power was completely canceled, i.e. converted into heat, only a fraction

  of this braking power is now lost.

  Thanks to the connection in accordance with the invention, the cost

  full braking adapts to the winding diameter. That if-

  indicates that a high braking torque is assumed for a large winding diameter; the braking torque is

  consequently smaller for a small winding diameter-

  is lying. For the braking function, the braking torque is automatically adjusted to the winding diameter. A higher braking torque is automatically set for the stop function. The particularly important point

  is that, precisely when the winding diameter

  The accumulation drum is also small, and when the maximum angular speed is consequently reached, the maximum ratio between the braking torque and the stopping torque is also associated with this service condition. So precisely, so far, the relationships between

  couples were even negatively altered in si-

  unfavorable service kills, the relationships between

  ples, respectively also the relationships between pressures,

  now automatically adapt to the operating conditions

  specific defects. If during the reeling process an immobilization occurs for any reason, the

  steel rope patina on the capstan. This results in an additional

  pressure of the pressure in the hydraulic circuit. Via the control duct, between the reduction / braking valve and the hydraulic duct leading to the engine

  capstan, a change in the relationships between the

  is caused in said reduction / braking valve.

  As a result, the charge pressure prevailing in the valve

  reduction / braking is immediately transformed into the pres-

  adjustment valve. The holding pressure of the

  the hydraulic motor of the accumulation drum

  finds in this way increased, which immediately causes the increase

  indication of the braking torque which then corresponds to the

ple maximum antagonist.

  During a normal reeling process, the branch-

  ment according to the invention causes constant transport of the absorption volumes towards the hydraulic motor which, due to the variation of the winding diameter on

  the accumulation drum, requires a larger volume of ab-

  sorption. Another advantage is that the arrangement

  of the new connection is reflected globally, in the

  hydraulic cooking, with less heat generation, so that less heat must also be dissipated. This has a positive influence on the

  operation of hydraulic power packs. Operating costs

  operation, as well as maintenance costs, are con-

sequent lowered.

  The invention is discussed in more detail below, at

  the support of an exemplary embodiment illustrated in the drawing.

  For a better understanding, the branch diagram-

  hydraulically has been illustrated in a technically schematic way, that is to say that it does not represent all the means which are naturally necessary in practice, such as valves, throttles, accumulators,

  reservoirs, etc., but which nevertheless have a characteristic

  secondary mother for the explanation of the inventive idea.

  The drawing illustrates schematically a fric winch

  tion 1 and an accumulation drum 2. A steel rope 3,

  symbolized by a dotted line and extending between these two elements

  , is guided through the friction winch 1 and opens into a tubular pipe not shown

  in that case. The friction winch 1 is coupled by the

  through a transmission 4, to a capstan motor 5.

  By means of a transmission 6, the storage drum

  mulation 2 is connected to a motor 7.

  Both the motor 5 of the capstan and the motor 7 of the drum

  bour, are supplied with hydraulic fluid by a pump 8 to

  variable displacement. Hydraulic lines 9, 10 are connected

  connected to this pump 8. The pumping pressure P1 is applied

  quée to a distributor 11 of the type 4/2 through the con-

  hydraulic hose 9, just as it is applied, by the

  through a control conduit 12, to a connection

command 13 of said distributor 11.

  The connection with the capstan motor 5 is ensured by a hydraulic conduit 14, of a bifurcation 15 up to

input side of said motor 5.

  The hydraulic conduits 9, 10 are connected by the

  end of a transverse conduit 16. A pressure limiter

  sion 17 is integrated in this transverse conduit 16. A con-

  return line 18 starts from the motor 5 of the capstan, and gains a bifurcation 19 (connection) in the hydraulic conduit 10. The transverse conduit 16 communicates with the hydraulic conduit

  9 via a 19 'bifurcation (connection).

  A pressure switching valve 20, associated

  ciée to a bypass conduit 21, is provided in the return conduit 18. The direction of flow, in the conduit

  bypass 21, is pre-established by a non-return valve 22.

  Distributor II working connections of type 4/2

  can be switched to the drum motor 7 via the

  medium of hydraulic lines 23, 24. A valve 25 for

  duction / braking (pressure limiter) is integrated in the conduit 23. Thanks to a non-return valve 26, this valve 25

  can be freely traversed by a flow by means of a con-

  duit 29, from a fitting 27 to a fitting 28, opposite the

  normal direction of switching on.

  The reduction / braking valve 25 is connected, by means of a control conduit 30, to the hydraulic conduit 14 leading

to the capstan motor 5.

  The reeling process involves the conditions of

service set out below.

  Via hydraulic lines 9 and 14,

  the pumping pressure P1 acts on the motor 5 of the capstan.

  This pumping pressure P1 is simultaneously applied to the distributor 11 of the 4/2 type, as well as to the control fitting 13 via the control conduit 12. The distributor 11 is, in this way, switched to the crossing position . Of

  there, the pumping pressure Pl acts on the valve 25 of reduction

  tion / braking. By means of conduit 29 and via

  non-return valve 26, this valve can be freely

  run by a flow towards the motor 7 of the drum.

  The pumping pressure P1 generates, on the motor of the capstan, a specific torque md2 causing

  a pull of the rope which unwinds this steel rope 3 from the drum

  accumulation bour 2. Due to the lever arm exerted by the winding diameter, the pulling of the rope acting on the drum 2 imposes a specific torque md1 on the motor 7 of the drum. Following the presence of the transmission

  reduction gear 6, said motor 7 therefore develops

  load pressure DL in the hydraulic circuit.

  For structural considerations, the charge pressure DL is always higher than the pumping pressure

  Pl- From a purely technical point of view concerning the branch

  The charge pressure DL and the pumping pressure Pl

  offset each other on the reduction / braking valve 25.

  As the load pressure DL is higher than the pumping pressure P1, the non-return valve 26 closes and the motor

  7 of the drum works by opposing, on the one hand, the pressure

  pumping pressure P1 and, on the other hand, to valve 25. The difference

  pressure rence, between load pressure DL and pres-

  pumping pressure P1, is suppressed via the

  valve 25, from which the desired braking torque results

  imposed on the storage drum 2 or on the motor 7 of the

drum.

  The relationships between the winding diameters vary continuously on the accumulation drum 2. This implies a permanent variation in the load pressure DL for the diameters dx considered. This associated load pressure DL results from the absorption volume of the two hydraulic motors and 7; reduction ratios i1, i2 in the

  transmissions 4 and 6; of the existing report respectively in

  tre the winding diameters d1 of the friction winch 1, and the winding diameter dx of the accumulation drum 2;

  as well as the activation ratio of the reduction valve 25

  tion / braking. This activation ratio is a magnitude

  characteristic of valve 25 which is predetermined structural-

  LEMENT, and it is conditioned by opposite surfaces inside said valve 25, and can be biased

by pressure.

  The control conduit 30 is provided between the reduction / braking valve 25 and the hydraulic conduit 14. In this way, said valve 25 is placed under the influence of the pumping pressure P1. If it happens, during the unwinding of the

  steel rope 3, that this rope 3 skates on the fric winch

  tion 1, the pumping pressure P1 is removed. Given

  that this pumping pressure Pl also prevails in the con-

  control line 30, this then results in a modification

  tion of the relationships between pressures, because the pressure

  load DL is immediately transformed into a pressure

  valve adjustment DE 25. Thus, the pressure of

  hold intended for the accumqLatSizn 2 drum increases up to

  that at the maximum value, so that Le. braking torque,

  imposed in normal service, is further increased to reach

dre the stop torque.

  It goes without saying that numbers r: zcfications can

  be made to the hyz-uLiue connection Write and represent

  without departing from the framework of the information.

Claims (4)

-R E V E N D I C A T I 0 N S-   1. Hydraulic connection for controlling hydraulic motors (5, 7) associated with a friction winch (1) in   upstream of which an accumulation drum (2) is installed, the   said motors being connected to a hydraulic pump (8) by means of hydraulic conduits (9, 10), connection in which a respective pressure relief valve (25, 17) is integrated in one considered of the hydraulic conduits (9, 10) connecting the hydraulic pump (8) to the hydraulic motors (5, 7), and in a transverse conduit (16) connecting the hydraulic conduits (9, 10) connected to the hydraulic pump (8), connection characterized in that '' a distributor (11),   the control of which can be reversed depending on the direction   winding, is provided in the hydraulic conduits   (9, 10) gaining the hydraulic motor (7) of the storage drum   mulation (2), between the connections (19, 19 ') of the trans-   versal (16) with the hydraulic conduits (9, 10) leading to the hydraulic pump (8), and the pressure relief valve (25) integrated in the hydraulic conduit (23) leading to the hydraulic motor (7) of the accumulation drum (2); and by the fact that the pressure relief valve (25) is produced under the   form of a reduction / braking valve, which can be in-   influenced by the pressure prevailing in the hydraulic conduit (14) leading to the hydraulic motor (5) of the friction winch (1). 2. Connection according to claim 1, characterized in that a control connection of the valve (25) reduction / braking, and the hydraulic conduit (14) leading to the hydraulic motor (5) of the friction winch (1) , are connected to each other via a control conduit (30).   3. Connection according to claim 1 or 2, charac-   terrified by the fact that the distribution control fittings   tor (11) are subject to the influence of the prevailing pressure   in the hydraulic lines (9, 10) leading to the hy-   hydraulics (7) of the accumulation drum (2).   4. Connection according to any one of the claims.   1 to 3, characterized in that the distributor (11) is a 4/2 type distributor.