FR2499499A1 - DEVICE FOR ADJUSTING THE RAMP OF TANKS, FLOATING BRIDGES OR THE LIKE - Google Patents

Abstract

THE INVENTION RELATES TO A RAMP ADJUSTMENT DEVICE INTENDED TO ESTABLISH A BRIDGE BETWEEN FLOATING BRIDGES, BINS OR THE LIKE, AND SHORES HAVING DIFFERENT INCLINATIONS AND HEIGHTS. THE PRINCIPLE OF THE INVENTION CONSISTS OF LEVELING THE CURVE OF THE MOMENT OF BENDING, SO AS TO BETTER BALANCE IN THE CONNECTION ZONE OF THE RAMP WITH THE NEAREST BRIDGE BEAM AND TO ADAPT IT TO THE MOMENT OF BENDING OF THE PART FLOATING BRIDGE POWER PLANT. TO OBTAIN THIS RESULT, A SWITCHING DEVICE SENSITIVE TO THE LOAD AND INTENDED TO INTERRUPT AND OR REVERSE THE HYDRAULIC FLUID CURRENT BETWEEN BOTH SIDES OF THE PISTON OF THE RAMP ADJUSTMENT CYLINDER IS ASSOCIATED WITH THIS CYLINDER IN ITS HYDRAULIC CIRCUIT. THE SYSTEM MAY BE CONSTITUTED EITHER BY A PRESSURE ACCUMULATOR WITH LOW PRESSURE OF PRE-CONTROLLING AND PRESENTING THE SAME PISTON-PISTON ROD RATIO AS THE RAMP ADJUSTMENT CYLINDER, OR ACCORDING TO A SIMPLER FORM OF IMPLEMENTATION BY A HYDRAULIC COMPENSATION SWITCH A FLOAT. IN ANY CASE, A SAFETY VALVE WITHOUT INTERMEDIATE DUCTS AND SET TO THE DESIRED BENDING MOMENT IS ASSOCIATED DIRECTLY WITH THE RAMP CYLINDER.

Description

The present invention relates to a device for adjusting ramps of tanks,

  floating bridges or the like, in which the bridge beam and the ramp which constitutes the connection with the

  bank are pivotally connected to each other by the

  through a point of rotation, hydraulic cylinders

  being provided in the area of the point of rotation for adjustment

  age of the ramp, and a pressure that automatically adapts to the load supported by the ramp can be applied to

  surfaces of the pistons of these cylinders.

  To bridge flat and inclined banks,

  a bank ramp of sufficient length must be available.

  The long support length of the latter however causes the appearance of undesirable or even inadmissible bending moments, in particular at the connection,

  rigid in flexion, of the bridge beam of the floating bridge.

  These bending moments are in any case much more important.

  as long as the normal bending moment in the central part

  xed from the floating bridge. For reasons of standardization and exchangeability of the component parts of the floating bridge, it has been necessary, to date, to adapt the dimensions of all the component elements of the floating bridge, including

  those used for the central part of the floating bridges

  tants or tubs, to the thickness of the ramp depending on

  these high bending moments in the connection area.

  It is not possible to connect the ramps to the

  very articulated bridge to avoid the shortcomings mentioned above. At the connection point, when

  heavy loads circulate on the ramp, form slumps

  of the route taken. The floating bodies located on the bank side sink much more into the water than

  those located in the central part of the floating bridge.

  This has the consequence that due to standardization

  and the necessary exchangeability which have already been mentioned-

  born, the floating bodies must also have in the

  central part of the floating bridge of larger dimensions

  aunts, such as those necessary for floating bodies located on the bank side. As for the large dimensions of the floating bodies located on the bank side,

  they are necessary to increase their ascent thrust-

  nelle and therefore keep within certain limits the

  that we see in the track.

  The subject of the invention is therefore the problem of the connection

  ment of the ramp to the bridge beam so as not to exceed on the one hand the bending moment of the central part of the floating bridge or of a ferry, and on the other hand to maintain at

  a low level the sinking of the floating body located on the side

shore.

  The flexibility needed to connect the ramp could be obtained in the simplest way by providing

  safety valves on the hydraulic cylinders which

  were fitted with boom adjusters, these valves limited

  both the maximum oil pressure and therefore the maximum bending moment. If these valves open, the ramp supports then lift off the bank after the load has passed beyond the ramp connection, and when the next load passes, the ramp must again, by l By means of a hand switch, be lowered by the available hydraulic system. This simple measure

  in itself, however, has been shown to have major

  for the operation of a floating bridge, in particular

culier in night use.

  The Applicant has itself carried out other research using a pressurized gas accumulator mounted in the

  hydraulic circuit of the boom adjustment cylinders, and

  installed upstream of the safety valves on the cylinders. The pressurized and spring-loaded gas accumulators were in this case arranged in such a way that when the pressure of

  preload was exceeded in the accumulator, the oil pro-

  coming from the ramp cylinders could be taken up by the battery

  mulator with a relatively slight increase in pressure

  if we. After the charge has passed, the accumulator returns the pressure oil to the boom cylinders. This system

  at least avoided the inconvenience of seeing the

  ramps lift off the bank when the connection-

  The ramp was no longer subjected to a load.} but this embodiment also presented a whole series of drawbacks. This is how a gas accumulator under

  pressure and spring can only be used in lini-

  narrow temperature tests. When we reach the limit of 00C, its use is no longer possible. In addition, the pressure of the gas prevailing in the accumulator varies greatly.

  depending on the external temperature, which means that

  because of this fact, but also generally

  However, the gas pressure must be monitored and maintained at its set value. A rupture of the pipes reaching the accumulator or a failure of this accumulator can capsize the tank or flood the floating bridge on which such a device is mounted. Finally, when the pipes reaching the hydraulic fluid tank are too long,

  suction problems may arise on the cover side

  cylinder key and cause vacuum to form. The garnishes

  The ramp adjustment cylinders are in danger. he

  can also be established in the whole system an elas-

not calculable.

  A ramp adjustment device of similar type is known from German patent DE-AS 2 900 861. In the hydraulic system provided in this case, the surfaces of the piston of a

  cylinder and piston assembly are subjected to elastic pressure

  progressive tick when there is a load. The goal to reach

  dre is that for example the first pontoons of the floating bridge

  which are close to the bank do not sink too deep-

  lying in the water, or even underwater, when a vehicle passes

  on them. To obtain the elastic pressure with progressive effect

  if there is also a filled pressure accumulator

gas under pressure.

  To provide a solution to the problem posed, and in par-

  to avoid the mentioned disadvantages of the provisions

  known or at least those who have been the subject of

  know, it is proposed according to the invention that starting from the dispo-

  sitive described in the preamble, the two surfaces of the piston of a hydraulic cylinder are subjected, via a hydraulic line connecting the two sides of the piston and depending on the load applied to the ramp, a pressure adjusting automatically, that a valve

249949-9

  safety is provided directly in the hydraulic line

  against the hydraulic cylinder and be adjustable on the

  bending which can be absorbed by the connection area

  the boom with the floating body, and that a switching device sensitive to the load and allowing automatic interruption and / or reversal of the hydraulic fluid current between the

two sides of the cylinder.

  According to a preferred embodiment, this load-sensitive switching device is in the form

  a pressure accumulator, the pre-pressure of which

  te is weak, in which is provided a piston which can be subjected to a pressure on its two sides and whose ratio

  piston-piston rod is the same as that of the hydraulic cylinder

  used for adjusting the ramp.

  When the pressure set by the safety valve is exceeded, the hydraulic fluid which is discharged from the boom adjusting cylinder in this load-sensitive switching device is discharged at a low preload pressure. Due to the piston-to-piston rod ratio which is

  the same, you can immediately replace the amount of fluid

  missing hydraulic on the opposite side of the piston of the

  ramp adjustment rin, which avoids problems

  that continue to occur and have been de-

  crits. When the load has passed over the ramp, the latter is applied by its point on the bank due to its own weight.

  To promote the functioning of the

  load-sensitive mutation, we can additionally have, in

  its cylinder, a spring acting on one side of the piston.

  The pretension exerted by this spring facilitates the

  clinching of the ramp while maintaining its point applied to the bank. Therefore, one can also and possibly overcome the own friction of the bearings and pistons

  to be taken into account. When the ramp is no longer under

  put under a load, the hydraulic fluid returns to the

  ramp adjustment rin which it had previously been

  crowd. According to a simple embodiment, the load-sensitive switching device can be constituted in the form of a hydraulically compensated switch controlled by a float and comprising a compensating valve mounted in the hydraulic line and opening or closing.

  mant depending on the position of a control float.

  When the boom connection is not subjected to a load, the free joint is constituted by an open connection between the boom cylinder and the hydraulic fluid reservoir. When it is subjected to a load, a connection is established by a depression in the water of the diver

  which is set in advance, which allows a connection

  rigid bending ramp having a bending moment

  calculated predetermined and admissible. According to this form of reaction

  However, it is necessary that the actual weight of the ramp is large enough so that after the passage of the load, the tip of the ramp comes to apply

  with security on the bank. In addition, to avoid problems

  As the suction continues to occur, the hydraulic fluid tank should be located a short distance from the

ramp adjustment cylinder.

  In any case, the invention makes it possible to obtain an automatic adjustment of the angle between the ramp and the floating body and thus a leveling of the bending moment in the articulation zone starting from a determined angular position of the ramp. relative to the floating body associated with it, depending on the fulcrum of the end of the ramp on the bank and according to the load applied to the ramp in the

  area of the boom articulation with the floating body.

  The two embodiments according to the invention can

  can be used in the overall hydraulic circuit which is already equipped with corresponding valves. Furthermore, it

  it is possible to install additional pilot check valves

  directly into the cylinder to further increase

  more security in the event that a pipe breaks.

  The invention will be described below in more detail below.

  of two exemplary embodiments which are shown in the accompanying drawings in a purely schematic manner and by way of examples, drawings in which FIG. 1 represents a floating body belonging to a floating bridge and situated on the side of the bank, this body comprising a ramp and a ramp adjustment cylinder, FIG. 2 represents a floating body of this type

fitted with a control float.

  FIG. 3 is a hydraulic switching diagram of a hydraulic control system with a spring accumulator, and FIG. 4 represents a hydraulic control diagram

using a control float.

  In Figure 1 is shown, by way of example only

  ple, the floating body 1 which is associated with the ramp 2 and which

  is connected to this ramp 2 in an articulated manner at the connection point

  cord 3. The adjustment cylinder 4 is articulated by its two

  parts between the ramp 2 and the floating body 1, in the vicinity

  ge of the connection point 3. The angular position of the

  ramp 2 relative to the deck of the floating body 1 can be

  slipped by the adjustment cylinder to which this ramp is articulated.

  When the free end 5 of the ramp is applied to the cradle

  ge 6, this angular position depends on the nature and the

bank height.

  If the ramp 2 or the connection area 3 of the ramp 2 with the floating body 1 of the amphibious vehicle associated with it is subjected to a load for example by a vehicle

  heavy earth which arrives or which leaves, moments of fle-

  Very high xions appear in the area of the joint 3. These bending moments can be easily attenuated,

  if it is possible to adjust ramp 2 according to the load

  ge. According to FIG. 3, this result is obtained by means of a

  spring accumulator 7 which is provided in the hydraulic circuit

  The ramp adjustment cylinder 4. This ramp adjustment cylinder 4 comprises a piston 8, the two faces of which can be

  under pressure, and it is also provided in the ac-

  spring accumulator 7 a piston 9 on both sides of which pressure can be applied. The chamber 10 of the ramp adjustment cylinder 4 is connected by a pipe 11 with the chamber 12 of the spring accumulator 7 in which is mounted, in the embodiment shown, a spring 13 acting on the piston 9. A pressurized gas accumulator is not very suitable, because the accumulators with

  pressurized gases of this type do not operate at times

  low temperatures and the fact that the gas pressure must also be constantly monitored. Chamber 14 of the cylinder

  ramp adjustment 4 is connected by a line 15 to the second

  chamber 16 of the spring accumulator 7, via

diary of a safety valve.

  If the ramp 2 is subjected to a load, the hy-

  hydraulics pass from chamber 14 of ram adjustment cylinder

  eg 4 in chamber 16 of the spring accumulator 7. As a result, hydraulic fluid passes from chamber 12 of

  the spring accumulator 7 in the chamber 10 of the return cylinder

  ramp glage 4. The spring 13 contained in the spring accumulator 7 is then subjected to a load. The condition for the described hydraulic fluid flow to take place

  is that the safety valve 17 which is provided in the circuit

  hydraulic cooked and which is mounted directly on the cylinder

  Ramp adjustment 4 opens for a predetermined pressure.

  The ramp can now change its angular position depending on the load applied to it, and the bending moment is advantageously influenced in the direction of

leveling of its curve.

  When a load is no longer applied, the hydraulic fluid

  lique follows a reverse course. The ramp's own weight and

  the spring 13 then facilitate this return.

  The hydraulic fluid flows practically without pressure in one direction and in the other between the various chambers of the

  cylinders. These movements are carried out completely automatically.

  as a function of the pressure applied by the load on

  ramp 2. The installation hardly needs any

maintenance.

  As shown in Figures 2 and 4, another possibility

  The element consists of providing on the floating body 1 and in a suitable position, a control float 1o mounted on a pivoting lever 19, by means of which a compensating valve which is mounted in the hydraulic circuit between the two 249 949th chambers 10 and 14 of the ramp adjustment cylinder 4 can be

  open or closed. This opening or closing is

  performed as a function of the angular position of the lever 19 and therefore of the position of the control float iG mounted at its free end. The other valves shown in the two diagrams

  switching switches are associated with the hydraulic circuit

  usual procedure for operating the adjustment cylinder

  ramp 4 and do not deserve to be described in detail.

249949,

Claims (4)

- EVENTS -   1. - Device for adjusting tank ramps, floating bridges   tants or the like, in which the bridge beam and the ram   pe which constitutes the connection with the bank are pivotally connected to each other via a point of rotation, hydraulic jacks being provided in the area of the point of rotation for adjusting the ramp, and a pressure automatically adapting to the load supported by the ramp which can be applied to the surfaces of the pistons of these jacks,   characterized in that the two faces of the piston of a hy-   hydraulics (4) are subjected, via a   hydraulic head (15,11) connecting the two sides (10,14) of the piston   tone and depending on the load applied to the ramp, at a pressure that adjusts automatically, in that a   safety (17) is provided directly on the hydrau-   lique (15) going to the hydraulic cylinder (4) and is adjustable on the bending moment which can be absorbed in the connection area of the ramp (2) with the floating body (1), and in that it is provided in the hydraulic line (15,11)   a load-sensitive switching device which allows   both automatic interruption and / or current reversal   hydraulic fluid between the two sides of the cylinder of the rin (4).   2. - Device according to claim 1, characterized in that the load-sensitive switching device is constituted in the form of a pressure accumulator (7) whose pre-stress pressure is low, in which a piston (9 ) can be subjected to pressure on both sides and whose piston-to-piston rod ratio is   same as that of the hydraulic cylinder (4) used for the adjustment boom age.   3. - Device according to claim 2, characterized in   what a spring (13) exerting its action on a face of the cy-   lindre is also mounted in the pressure accumulator (7).   4. - Device according to claim 1, characterized in that the load-sensitive switching device   consists of a hy- compensated switch   hydraulically controlled by a float and includes a compensation valve (20) mounted on the hydraulic line (11,15) - and opening or closing depending on the position of a control float (18).